After the assassination of Mahatma Gandhi, Krishan wrote a song Suno Suno Aye Duniyawalon, Bapu Ki Yeh Amar Kahani. The song was sung by Mohammed Rafi He also wrote "Jahan daal daal par sone ki" for Sikandar-E-Azam.
He is is known for his association with the composer C. Ramchandra. He worked with several other music directors including Shankar-Jaikishan, Ravi, Rajesh Roshan, Madan Mohan.
In the mid-1940s, Krishan shifted to Bombay (now Mumbai) to become a screenwriter in the Hindi film industry. His first screenplay was Janta (1947). His first film as a lyricist was Zanjeer (1947). He was first noted for the script and lyrics of the Motilal-Suraiya starrer Aaj Ki Raat (1948). His first success as a lyricist came with the films Badi Bahen (1949) and Lahore (1949).
The was the film in which Rajinder Krishan paired with to make some very memorable songs.
In 1953, he wrote 4 songs for Anarkali.
He won Filmfare Award for best lyricist for the movie Khandan (1965) for the song "Tumhi mere mandir, tumhi meri pooja".
He died on 23 September 1987 in Mumbai.