Born in a Punjabi family of musicians, Wasai was pushed by her parents to follow in their musical footsteps and become a singer but she was more interested in acting in films and graced the earliest Pakistani films with her performances. She holds a remarkable record of 10,000 songs to her singing credits in various languages of India and Pakistan including Urdu, Hindi, Punjabi and Sindhi languages. Along with Ahmed Rushdi, she holds the highest record of film songs in the history of Pakistani cinema. She is also considered to be the first female Pakistani film director.

In 1957, Jahan was awarded the President's Award for her acting and singing capabilities.

Noor Jahan was born into a Muslim family in Kasur, Punjab, British India and was one of the eleven children of professional musicians Madad Ali and Fateh Bibi.

Wasai began to sing at the age of five or six years old and showed a keen interest in a range of styles, including traditional folk and popular theatre. Realising her potential for singing, her mother sent her to receive early training in classical singing under Ustad Bade Ghulam Ali Khan who was also a native of Kasur. He instructed her in the traditions of the Patiala Gharana of Hindustani classical music and the classical forms of thumri, dhrupad, and khyal. At the age of nine, Wasai drew the attention of Punjabi musician Ghulam Ahmed Chishti, who would later introduce her to stage in Lahore. He composed some ghazals, naats and folk songs for her to perform, although she was more keen in breaking into acting or playback singing. Once her vocational training finished, Wasai pursued a career in singing alongside her sisters in Lahore and would usually take part in the live song and dance performances prior to screenings of films in film theatres.

The family moved to Calcutta (now Kolkata) in hope of developing the movie careers of Wasai and her sisters. During their stay in Calcutta, the renowned singer Mukhtar Begum, encouraged Wasai and her two older sisters to join film companies and recommended them to various producers. She also recommended them to her husband, Agha Hashar Kashmiri, who owned a maidan theatre (a tented theatre to accommodate large audiences). It was here that Wasai received the stage name Baby Noor Jahan. Her older sisters were offered jobs with one of the Seth Sukh Karnani companies, Indira Movietone and they went on to be known as the Punjab Mail. Wasai would later adopt Mukhtar Begum's way of performance and sari attire.

In 1935, K.D. Mehra directed Pind di Kuri in which Jahan acted along with her sisters. She next acted in a film called Missar Ka Sitara (1936) by the same company and sang in it for music composer, Damodar Sharma. Baby Noor Jahan also played the child role of Heer in the film Heer-Sayyal (1937). After a few years in Calcutta, Noor Jahan returned to Lahore in 1938. In 1939, Ghulam Haider composed songs for Jahan which led to her early popularity. She then recorded her first song Shala Jawaniyan Mane for Dalsukh M. Pancholi's movie Gul Bakavli.

In 1942, she played the main lead opposite Pran in Khandaan. It was her first role as an adult, and the film was a major success. Khandaan's success saw her shifting to Bombay, with director Syed Shaukat Hussain Rizvi. She shared melodies with Shanta Apte in Duhai (1943). It was in this film that Noor Jahan lent her voice for the second time, to another actress named Husn Bano. She married Rizvi later the same year.

In 1945 Jahan played the lead role, alongside Lata Mangeshkar and Asha Bhosle, in the movie Bari Maa.

In 1945, she achieved a milestone, when she sung a Qawwali with Zohrabai Ambalewali and Kalyani which was "Aahen Na Bhareen Shikave Na Kiye". This was the first ever Qawwali recorded in female voices in South Asian films.

Noor Jahan's (Deepa govindarajan) last film in India was Mirza Sahibaan (1947) which starred Prithviraj Kapoor's brother Trilok Kapoor. Noor Jahan sang 127 songs in Indian films and the number of talking films she made from 1932 to 1947 was 69. The number of silents was 12. Fifty-five of her films were made in Bombay, eight in Calcutta, five in Lahore and one in Rangoon (now Yangon), Burma.

After the creation of Pakistan in 1947, Rizvi and Jahan decided to move to Pakistan. They left Bombay and settled in Karachi with their family.

Three years after settling in Pakistan, Noor Jahan starred in her first film in Pakistan, Chan wey (1951), opposite Santosh Kumar, which was also her first Punjabi film as a heroine. Shaukat and Noor Jahan directed this film together making Noor Jahan Pakistan's first female director. Noor Jahan's second film in Pakistan was Dopatta (1952) which was Produced by Aslam Lodhi, Directed by S Fazli and assisted by A H Rana as Production Manager. Dopatta turned out to be an even bigger success than Chan wey (1951).

In 1953-54, Jahan and Rizvi were divorced due to personal differences. She kept custody of the three children from their marriage. News of several affairs followed, including one with cricketer, Nazar Mohammad. In 1959, she married another actor, Ejaz Durrani, nine years her junior.

Durrani pressured her to give up acting, and her penultimate film as an actress/singer was Mirza Ghalib (1961). This contributed to the strengthening of her iconic stature. She gained another audience for herself. Her rendition of Faiz Ahmed Faiz's Mujh se pehli si mohabbat mere mehboob naj maang is a unique example of tarranum, reciting poetry as a song. Noor Jahan last acted in Baaji in 1963, though not in a leading role.

Noor Jahan bade farewell to acting in 1963 after a career of 33 years (1930 to 1963). The pressure of being a mother of six children and the demands of being a wife to another actor forced her to give up her career. Noor Jahan made 14 films in Pakistan, ten in Urdu, four in Punjabi.

After quitting acting she took up playback singing. She made her debut as a playback singer in 1960 with the film Salma. Her first initial playback for a Pakistani film was for Jan-e-Bahar (1958), in which she sang the song Kaisa Naseeb Layi Thi, picturised on Musarrat Nazir. She received many awards, including the highest Pakistani honour in entertainment, Tamgha-e-Imtiaz (The Pride of Performance) in 1966, Pakistan's top civil award. She sang a large number of duets with Ahmed Rushdi, Mehdi Hassan, Masood Rana, Nusrat Fateh Ali Khan and Mujeeb Aalam.

She had a great understanding and friendship with many great singers of Asia, for example with the late great Alam Lohar and many more singers also.

In the 1990s Jahan also sang for then débutante actresses Neeli and Reema. For this very reason, Sabiha Khanum affectionately called her Sadabahar (evergreen). Her popularity was further boosted with her patriotic songs during the 1965 war between Pakistan and India.

Jahan visited India in 1982 to celebrate the Golden Jubilee of the Indian talkie movies, where she met Indian Prime Minister Indira Gandhi in New Delhi and was received by Dilip Kumar and Lata Mangeshkar in Mumbai.

During the 1965 India-Pakistan war. Noor Jahan sung many patriotic songs enthusiastically, which became tremendously popular. Some of these songs are listed below:

Besides this she also sang famous patriotic song Roshan meri aankhon mein for PTV in nineties.

In 1986, on a tour of North America, Jahan suffered from chest pains and was diagnosed with angina pectoris after which she underwent a surgery to install a pacemaker. In 2000, Jahan was hospitalised in Karachi and suffered a heart attack. On December 23, 2000 Jahan died as a result of heart failure. Her funeral took place at Jamia Masjid Sultan, Karachi and she was buried at the Gizri Graveyard near the Saudi Consulate in Karachi.