He was also the pioneer in using the counter melody in film scores, employing technique of western music, ‘cantala’, where one line overlaps the other in contra-melody, recitative prose songs as in Roti (1942), besides he was the first one to start extensively using the Ragmala.

[5][6] Another important element that he introduced was western orchestration, using indigenous instruments both in the songs as well as in their melodic interludes, a trend that soon caught on and paved way for the musicals of Indian cinema today.

He got assignments from renowned Bengali poet, Kazi Nazrul Islam, all this got him into the notice of music director, Hiren Bose, and at whose behest he made his way to Bombay (Mumbai) in 1934.

Soon many more independent assignments came his way, most notably, 300 Days and After, Gramophone Singer, Hum Tum Aur Woh, Ek Hi Raasta, and Mehboob Khan's Watan (1938), Alibaba (1940), the classic, Aurat (1940), Bahen (1941), before working with him again, in Roti (1942), for which he also credited with the story and concept,[9] and which featured many songs by film's actress, Akhtaribai Faizabadi (Begum Akhtar), though they were deleted due to a contractual conflict (the music was recorded with HMV, while she was in contract with Megaphone Gramophone Company).

[6] He gave break to famed playback singer, Mukesh in Pehli Nazar (1945), singing 'Dil Jalta Hai to Jalne De', and to Talat Mahmood in Arzoo (1949), singing 'Aye Dil Mujhe Aisi Jagah Ley Chal' his first song in Bombay;[10] he was also behind the success of many singers such as Surendranath, Parul Ghosh, Amirbai Karnataki, Lata Mangeshkar and Roshan Ara Begum.

In 1942, he joined Bombay Talkies at an offer from Devika Rani, where he got his biggest hit, Gyan Mukherjee's Kismet (1943), starring Ashok Kumar and Mumtaz Shanti,[12] most remembered for the song, 'Papihaare', sung by his sister Parul Ghosh (wife of the renowned flautist, Pannalal Ghosh), the patriotic hit, 'Door hato ai duniyaa waalo', and 'Dheere dheere aare badal, mera bulbul so raha hai, shorgul na macha' sung by the actor, Ashok Kumar.

[11] In 1946, he left Bombay Talkies and set out as a freelancer, and later under the banner, ‘Variety Pictures’ owned by his wife, AshaLata Biswas, worked for four films, Laadli (1949), Laajawaab (1950), Badi Bahu (1951) and Humdard (1953), with KA Abbas Rahi (1952), songless Munna (1954), where he gave the background score, and Indo-Russian joint production, Nargis starrer, Pardesi (1957) and Char Dil Char Rahen (1959).

In early 1960s, he retired from the cinema, while still at the peak of his game, he shifted base to New Delhi, though he did one or two films in between like Mahesh Kaul's, Sautela Bhai (1962), his final film as a composer was, actor Motilal's directorial venture, Chhoti Chhoti Baatein (1965), starring Nadira and with Mukesh's 'Zindagi Khwab Hai Tha Hamein Bhi'.

Ashalata worked as an actress during the 1930s and 1940s, a period during which acting in films was considered disreputable and few women entered the industry; she also owned Variety Pictures, a film-making company.