Kumar a lot, especially in the late 50s and early 60s, resulting in Kumar developing into a great singer in the future years. S. D. Burman recorded Kumar's voice for Dev Anand's Munimji (1954), Taxi Driver (1954), House No. 44 (1955), Funtoosh (1956), Nau Do Gyarah (1957), Paying Guest (1957), Guide (1965), Jewel Thief (1967), Prem Pujari (1970), and Tere Mere Sapne (1971). He also composed music for Kumar's home production Chalti Ka Naam Gaadi (1958). Some of their songs were "Maana Janaab Ne Pukara Nahin" from Paying Guest (1957), "Hum Hain Rahi Pyar Ke" from Nau Do Gyarah (1957), "Ai Meri Topi Palat Ke Aa" from Funtoosh (1956), and "Ek Ladki Bheegi Bhaagi Si" from Chalti Ka Naam Gaadi. Asha Bhosle and Kishore performed duets composed by Burman including "Chhod Do Aanchal" from Paying Guest (1957), "Ankhon Mein Kya Ji" from Nau Do Gyarah (1957), "Haal Kaisa Hai Janaab Ka" and "Paanch Rupaiya Baara Aana" from Chalti Ka Naam Gaadi (1958) and "Arre Yaar Meri Tum Bhi Ho Gajab" from Teen Deviyan (1965). As a singer, Kumar's work with many music directors in this period includes "Ye Raatein Ye Mausam" and "Hum Toh Mohabbat Karega" from Dilli Ka Thug, "Piya Piya Mora Jiya" from Baap Re Baap, "Hello Hello Ji" from Bombay Ka Chor, "Micheal Hai Toh Cycle Hai" from Bewaqoof, "Ae Haseeno Nazneeno" from Chacha Zindabad, "Zaroorat Hai Zaroorat Hai" from Manmauji (1961), "Likha Hai Teri Ankhon Mein" from Teen Deviaan, "Suno Jaana Suno Jaana", "Pyaar Baatke Chalo" and "Kya Teri Zulfein Hai" from Hum Sab Ustaad Hai, "Khoobsurat Haseena" from Mr. X in Bombay, "Gaata Rahe Mera Dil" from Guide (1965), "Sultana Sultana" from Shreeman Funtoosh, "Machalti Hui" from Ganga Ki Lahren, "Mera Dil Meri Jaan" and "Pyar Ka Jaahan Hotel" from Jaalsaaz and "Yeh Dil Na Hota Bechara" from Jewel Thief (1967). Music director C. Ramchandra also recognized Kumar's talent as a singer. They collaborated on songs including "Eena Meena Deeka" from Aasha (1957). Kumar's work includes "Nakhrewaali" from New Delhi (1956) by Shankar Jaikishan, "C.A.T. Cat Maane Billi" and "Hum To Mohabbat Karega" from Dilli Ka Thug (1958) by Ravi, and "Chhedo Na Meri Zulfein" from Ganga Ki Lahren (1964) by Chitragupta. In 1968, Rahul Dev Burman worked with Kumar on the soundtrack of the film Padosan (1968), in which Kumar sang "Mere Saamne Wali Khidki Mein" and "Kehna Hai." Padosan was a comedy featuring