In 1948, Roshan came to Mumbai to find work as a Hindi film music director and became assistant of music composer Khawaja Khurshid Anwar in film Singaar. He somewhat struggled until he met the then famous producer-director Kidar Sharma, who gave him the job of composing for his film Neki aur Badi. While it was a flop, Kidar Sharma gave him another chance in his next film. Roshan emerged as a player on the Hindi film music scene with Baawre Nain which became a big musical hit. In the early 1950s, Roshan worked with singers Mohammad Rafi, Mukesh and Talat Mahmood. Malhar, Shisham, and Anhonee were some of the movies that he scored during the 1950s. During this time, he also composed the Meera bhajan which became a run-away hit, "Aeiri main to prem diwani mera dard na jane koyi" sung by Lata Mangeshkar for the movie Naubahar. He was not always commercially successful. He gave Indeewar and Anand Bakshi their first breaks in the Indian film industry as lyricists. Later, they became two of the most sought-after songwriters in Mumbai from the late 1960s onwards. Anand Bakshi was given his first break in 1956 by the music director Nisar Bazmi in his film Bhala Aadmi. Roshan gave Bakshi the film CID Girl, after Anand Bakshi wrote the four songs of Bhala Aadmi in 1956. Bhala Aadmi was released in 1958 after some delay. Together, Anand Bakshi and Roshan made a super hit musical filmDevar. The 1960s proved to be the golden age for Roshan and his music. His ability to mould folk music with Hindustani classical music became his trademark and resulted in successful movie musicals. During this time, Roshan gave hits such as "Na to karavan ki talaash hai from Barsat Ki Raat" and "Zindagi bhar nahi bhoolegi woh barsaat ki raat". Barssaat Ki Raat also was a "super hit" film of 1960. "Ab kya misaal doon" and "Kabhi to milegi, kahi to milegi", "Jo vada kiya vo nibhana padega", "Paao chhoon lene do", "Jo baat tujhmein hai" and "Jurm-e-ulfat pe", "Nigahen milane ko jee chahata hai" and "Laaga chunari mein daag", "Sansaar se bhaage phirte ho" and "Man re tu kaahe", and "Oh re taal mile" and "Khushi khushi kar do vida". He composed some melodies for the movie Mamta with lyrics by Majrooh Sultanpuri, "Rehte the kabhi jinke dil mein" and "Rahen Na Rahen Hum" sung by Lata Mangeshkar and her hit duet, "Chuppa Lo Yun Dil Mein Pyar Mera" with Hemant Kumar. Devar : "Aaya hai mujhe phir yaad woh zalim, guzara zamana bachpan ka"; "Baharon ne mera chaman loot kar"; "Duniya mein aisa kahan sab ka naseeb hai".
Nigahein Milane Ko Jee Chahta Hai film Dil Hi To Hai
Roshan's marked speciality was the film qawwali. He was widely hailed for their composition.
Death and legacy
Roshan had been suffering from chronic heart trouble for over 20 years. He died of a heart attack in Mumbai, Maharashtra, India, on 16 November 1967, age 50, leaving behind 3 sons and 1 daughter. He had a sudden heart attack while attending a social gathering.