Vangelis began his professional musical career working with several popular bands of the 1960s such as The Forminx and Aphrodite's Child, with the latter's album 666 going on to be recognized as a psychedelic "classic". Throughout the 1970s, Vangelis composed music scores for several animal documentaries, including L'Apocalypse Des Animaux, La Fête sauvage and Opéra sauvage; the success of these scores brought him into the film scoring mainstream. In the early 1980s, Vangelis formed a musical partnership with Jon Anderson, the lead singer of progressive rock band Yes, and the duo went on to release several albums together as Jon & Vangelis.

In 1981, he composed the score for the Oscar-winning film Chariots of Fire, which won him the Academy Award for Best Original Music Score. The soundtrack's single, "Titles", also reached the top of the American Billboard Hot 100 chart and was used as the background music at the London 2012 Olympics winners' medal presentation ceremonies.

In a career spanning over 50 years, writing and composing more than 52 albums, Vangelis is regarded as one of the greatest composers of electronic music of all time.

Vangelis was born 29 March 1943, near Volos, Greece. Largely a self-taught musician, he reportedly began composing at the age of four. He refused to take traditional piano lessons, and throughout his career did not have substantial knowledge of reading or writing musical notation. He studied painting—an art he still practises—at the Academy of Fine Arts in Athens. When he was six, Vangelis's parents enrolled him at a specialist music school in Athens. Vangelis said in an interview with Life, when asked about his lack of ability to read music:

In the early 1960s he was one of the founders of pop group The Forminx (or The Formynx), which became popular in Greece. Based in Athens, the five-piece band played a mixture of cover versions and their own material, the latter written mostly by Vangelis (with lyrics by DJ and record producer Nico Mastorakis) but still sung in English. The Forminx released nine hit singles and a Christmas EP before disbanding in 1966 at the peak of their success. A film being made about them at the time, which was initially directed by Theo Angelopoulos, was never fully completed, and the songs, composed for the movie, were never released. Vangelis spent the next two years mostly studio-bound, writing and producing for other Greek artists.

Around the time of the student riots in 1968, Vangelis founded progressive rock band Aphrodite's Child together with Demis Roussos, Loukas Sideras, and Anargyros "Silver" Koulouris. After an unsuccessful attempt to enter the UK, they found a home in Paris where they recorded their first single, a hit across much of Europe called Rain and Tears. Other singles followed, including two albums, which, in total, sold over 20 million copies. The record sales led the record company to request a third album, and Vangelis went on to conceive the double-album 666, based on Revelation, the last book in the Bible. One of the many remarkable features of this album is Irene Papas's guest participation (vocal on "Infinity"). Tensions between members during the recording of 666 eventually caused the split of the band in 1971, but the album was still released in 1972. Despite the split, Vangelis has since produced several albums and singles for Demis Roussos, who, in turn, contributed vocals to the Blade Runner soundtrack.

While still in Aphrodite's Child, Vangelis had already been involved in other projects. In 1970 he had composed the score for a film directed by Henry Chapier and called Sex Power (Demis Roussos sang vocals). In 1971, some jam sessions with a group of musicians at Marquee Studios in London had resulted in two albums' worth of material, unofficially released without Vangelis' permission in 1978, titled Hypothesis (aka Visions of the Future), and The Dragon. Vangelis succeeded in taking legal action to have them withdrawn. A more successful project was his scoring of wildlife films made by French filmmaker Frédéric Rossif. The first was L'Apocalypse des animaux, released in 1973. In 1972, the student riots of 1968 provided the inspiration for an album titled Fais que ton rêve soit plus long que la nuit (Make Your Dream Last Longer Than the Night), comprising musical passages mixed with news snippets and protest songs; some lyrics were based on graffiti daubed on walls during the riots.

In 1973 Vangelis' solo career began in earnest. His first "official" solo album was Earth, though it did actually feature a group of musicians including ex-Aphrodite's Child guitarist Silver Koulouris and also vocalist and songwriter Robert Fitoussi (better known as F.R. David of "Words" fame). This line-up, later briefly going out under the name "Odyssey", released a single in 1974 titled "Who", but that was Vangelis' last involvement with them. Later in 1974, Vangelis was widely tipped to join another prog-rock band, Yes, following the departure of Rick Wakeman. After a couple of weeks of rehearsals Vangelis wavered on the option of joining Yes and, the band had to detour and hire Swiss keyboard player Patrick Moraz instead, who later joined The Moody Blues. Vangelis did, however, become friends with Yes' lead vocalist Jon Anderson, and later worked with him on several occasions, including as the duo Jon & Vangelis.

After moving to London, Vangelis signed with RCA Records, set up his own studio, Nemo Studios, and began recording a string of electronic albums, such as Heaven and Hell (1975), Albedo 0.39 (1976), Spiral (1977), Beaubourg (1978), and China (1979). Parts of Heaven and Hell were later used as the theme to the PBS television series Cosmos by Carl Sagan. Two melodies from Albedo 0.39, "Alpha" and "Pulstar", and also one track from L'Apocalypse des animaux, "Création du Monde", were also used in Cosmos. Another part (the song "So Long Ago, So Clear"), featured guest vocals by Jon Anderson, marking the start of the partnership. Vangelis also contributed as a producer and keyboard player to the album Phos, by the Greek rock band Socrates Drank the Conium (later known simply as Socrates).

In 1979, Vangelis composed the score for another animal documentary by Frédéric Rossif, Opéra sauvage. Almost as well known as L'Apocalypse des animaux, the resulting soundtrack would bring him to the attention of some of the world's top filmmakers. The music itself would be re-used in other films (most notably the track "L'Enfant" in The Year of Living Dangerously (1982) by Peter Weir; the melody of same (in marching band format) can also be heard at the beginning of the 1924 Summer Olympics opening ceremonies scene in the film Chariots of Fire ) and television commercials (the track "Hymne", used in Barilla pasta commercials in Italy and Ernest & Julio Gallo wine ads in the US).

In 1981, Vangelis wrote the score for the film Chariots of Fire, set at the 1924 Summer Olympics. The choice of music was unorthodox as most period films featured traditional orchestral scores, whereas Vangelis' music was modern and synthesizer-heavy. The movie won the Academy Award for Best Picture and Vangelis won the Academy Award for Best Original Music Score. The opening theme of the film was released as a single in 1982, topping the American Billboard chart for one week after climbing steadily for five months.

Greek musician Stavros Logarides claimed Vangelis had copied the melody of "Titles" from one of his compositions called "City of Violets". Member of a 1970s band called Poll, and a friend of Vangelis at the time, Logarides sued Vangelis for plagiarism in 1987. At the court hearing, Vangelis set up synthesizers in the courtroom and played for the judge to demonstrate his compositional process. The judge ruled that any similarities in the melody were minor and "Titles" was a Vangelis original.

Other notable Vangelis soundtracks were Antarctica for the film Nankyoku Monogatari in 1983, and The Bounty in 1984. Vangelis also collaborated in 1981 and 1986 with Italian singer Milva, achieving success especially in Germany with the albums Ich hab' keine Angst and Geheimnisse (I have no fear and Secrets). The Italian language Nana Mouskouri album also featured her singing Vangelis composition "Ti Amerò". Collaboration numbers with lyricist Mikalis Bourboulis sung by Maria Farantouri included the tracks "Odi A", "San Elektra", and "Tora Xero".

The main theme for Chariots of Fire was also chosen by Apple's co-founder Steven P. Jobs for the public introduction of the first Macintosh computer, in January 1984.

In 1982, Vangelis collaborated with director Ridley Scott, to write the score for the science fiction film Blade Runner. Capturing the isolation and melancholy of Harrison Ford's character, Rick Deckard, the Vangelis score is as much a part of the dystopian environment as the decaying buildings and ever-present rain.

A disagreement led to Vangelis withholding permission for his performance of the music from Blade Runner to be released, and the studio instead hired a group of musicians dubbed "The New American Orchestra" to record the official LP released at the time. It took 12 years before the disagreement was resolved and Vangelis's own work was released in the United States, in 1994. The soundtrack was still incomplete, as the film contained some non-Vangelis tracks as well. Over the years a number of bootleg recordings of the Blade Runner soundtrack from unknown sources have been released, mostly targeted to collectors as "private releases", that contain most of the music cues (including the Ladd Company logo theme). An official three disc box set was released in late 2007 to commemorate the film's 25th anniversary: it contained the original 1994 album, a second disc containing some more of the missing music cues and a third disc of new Vangelis material inspired by Blade Runner. The 2007 release still lacks some incidental music, most notably the background music from the Taffey Lewis bar scene featuring vocals by Demis Roussos.

In 1992, Paramount Pictures released the film 1492: Conquest of Paradise, also directed by Ridley Scott, as a 500th anniversary commemoration of Christopher Columbus' voyage to the New World. Vangelis's score was nominated as "Best Original Score – Motion Picture" at the 1993 Golden Globe awards, but was not nominated for an Academy Award.

Carl Sagan's TV series Cosmos: A Personal Voyage uses several pieces composed by Vangelis, including the series' opening theme. In 1982 he performed for the Spanish television with Neuronium (Michel huygen and Carlos Guirao). This performance was recorded in 1996 in a CD entitled A separate affair. In 1983 Vangelis wrote the music for Michael Cacoyannis' staging of the Greek tragedy Elektra which was performed featuring Irene Papas at the open-air amphitheater at Epidavros in Greece. The same year Vangelis composed his first score for a ballet by Wayne Eagling. It was originally performed by Lesley Colier and Wayne Eagling himself at an Amnesty International gala in Drury Lane, but in 1984 the Royal Ballet School presented it again at the Sadler's Wells theater. In 1985 and 1986, Vangelis wrote music for two more ballets: "Frankenstein – Modern Prometheus" and "The Beauty and the Beast". In 1992, Vangelis wrote the music for the Euripides play, Medea, that featured Irene Papas. Though uncredited, Vangelis also wrote the theme music for the 1992 French motion picture, "La Peste" (The Plague) from director Luis Puenzo. In the 90's, Vangelis scored a number of undersea documentaries for French ecologist and filmmaker, Jacques-Yves Cousteau.

During 1980, six years after Vangelis decided against joining Yes, he and Jon Anderson, the lead singer of Yes, released their first album together, Short Stories, under the band name of Jon & Vangelis. They would eventually go on to release three more afterwards; The Friends of Mr. Cairo, Private Collection and Page of Life released in 1981, 1983, and 1991 respectively.

In May 2000, Vangelis composed the music as well as designed and directed the artistic Olympic flag relay portion of the closing ceremonies of the 2000 Sydney Olympic Games. While no official recording of Vangelis' composition for the 2000 Sydney Games exists, the music can be heard accompanying the presentation of the emblem of the 2004 Athens Games. His work from Chariots of Fire was heard during the 2012 Summer Olympics opening ceremony.

Vangelis performed live and released Mythodea, a predominantly orchestral rather than electronic piece that was originally written in 1993, and used by NASA as the theme for the Mars Odyssey mission in 2001. A year later, in 2002, Vangelis created the 2002 FIFA World Cup Official Anthem for the 2002 World Cup.

In 2004, Vangelis released the score for Oliver Stone's Alexander, continuing his involvement with projects related to Greece. Vangelis released 2 albums in 2007; the first was a 3-CD set for the 25th anniversary of Blade Runner, titled Blade Runner Trilogy and second was the soundtrack for the Greek movie, El Greco, titled El Greco Original Motion Picture Soundtrack.

On 11 December 2011, Vangelis was invited by Katara's Cultural Village in the state of Qatar to conceive, design, direct, and compose music for the opening of its world-class outdoor amphitheater. The event was witnessed by a number of world leaders and dignitaries participating in the 4th Forum of the United Nations Alliance of Civilizations held in the city of Doha. The event featured a light show by German artist Gert Hof and was filmed for a future video release by Oscar-winning British filmmaker Hugh Hudson.

In 2012, Vangelis re-tooled and added new pieces to his iconic Chariots of Fire soundtrack, for use in Chariots of Fire, the 2012 stage adaptation of the 1981 film of the same title.

For an artist of his stature, very little is known about Vangelis' personal life and he rarely gives official interviews to journalists. However, in a 2005 interview with The Telegraph, Vangelis talked openly about various parts of his life. He stated in the interview that he was "never interested" in the "decadent lifestyle" of his band days, choosing not to take drugs or drink alcohol. At the time of the Telegraph interview, Vangelis was involved in his third long-term relationship. When asked why he had not had children, Vangelis replied:

It is not known where Vangelis generally resides; he has stated that he "travels around", rather than settling down in one specific place or country for long periods of time. As a hobby, Vangelis enjoys painting; his first art exhibition toured South America in 2005.

Excerpts from other interviews mention that Vangelis has been married twice before. In a 1976 interview with Dutch music magazine Oor, the author wrote that Vangelis had a wife named Veronique Skawinska who was a photographer who had done some album art work for Vangelis. An interview in 1982 with Backstage music magazine suggests that Vangelis had previously been married to a singer named Vana Verouti, who had performed vocals on some of his records, performing for the first time with him on La Fête sauvage and later on Heaven and Hell.

As a musician, Vangelis relies heavily on synthesizers and other electronic approaches to music. Synthtopia, an electronic music review website, stated that Vangelis' music could be referred to as "symphonic electronica" because of his use of synthesizers in an orchestral fashion. The aforementioned review site went on to describe his music as melodic: "drawing on the melodies of folk music, especially the Greek music of his homeland." Vangelis' music and compositions have also been described as "...a distinctive sound with simple, repetitive yet memorable tunes against evocative rhythms and chord progressions." He often used vibrato on his synthesizers, which was carried out in a distinctive way on his Yamaha CS80 polyphonic synthesizer; varying the pressure exerted on the key to produce the expressive vibrato sound.

In an interview with Soundtrack, a music and film website, Vangelis talked about his compositional processes. For films, Vangelis stated that he would begin composing a score for a feature as soon as he sees a rough cut of the footage. In addition to working with synthesizers and other electronically based instruments, Vangelis also works with and is a conductor to orchestras. For example, in the Oliver Stone film Alexander, Vangelis conducted an orchestra that consisted of various classical instruments including sitars, percussion, finger cymbals, harps, and duduks.

Vangelis uses a technique of recording all tracks simultaneously on tape, using a Zyklus MIDI Performance System. The album Direct is named after the successor to the Zyklus which was being specially manufactured for him by the Zyklus MPS designers, Bill Marshall, Pete Kellock, and Mike Crisp.

France made Vangelis a Knight of the Order of Arts and Letters in 1992. In 1995, Vangelis had a minor planet named after him (6354 Vangelis) by the International Astronomical Union's Minor Planet Center (MPC) at the Smithsonian Astrophysical Observatory; the name was proposed by the MPC's co-director, Gareth V. Williams, rather than by the object's original discoverer, Eugène Joseph Delporte, who died in 1955, long before the 1934 discovery could be confirmed by observations made in 1990. NASA conferred their Public Service Medal to Vangelis in 2003. The award is the highest honour the space agency presents to an individual not involved with the American government. Five years later, in 2008, the board of the National and Kapodistrian University of Athens voted to make Vangelis an Honorary Doctor, making him Professor Emeritus at their Faculty of Primary Education. In June 2008, the American Hellenic Institute honoured Vangelis with an AHI Hellenic Heritage Achievement Award for his "exceptional artistic achievements" as a pioneer in electronic music and for his lifelong dedication to the promotion of Hellenism through the arts.

The American Film Institute nominated Vangelis' scores for Blade Runner and Chariots of Fire for their list of the 250 greatest film scores.