Kenny formed his first band whilst in high school and between then and the early 1970s, he toured the club circuit. In 1968 he landed his first recording contract with Warner Bros. Records, and from that point until 1977 issued a number of singles that failed to break the charts. He also recorded for Buddah and Laurie. One of Kenny's early releases, "Happiest Man", is now highly collectible and sells for high sums at auctions .
It was not until 1978 after moving to England that he scored his first hit single with "New York, New York (So Good They Named It Twice)" (an ode to his hometown), which spent two months in the UK Singles Chart, with its parent album Made It Through The Rain going Top 20 the following year. Another single on the RCA record label, "Fantasy", proved to be another chart hit in 1980. His composition "I Could Be So Good For You" was recorded by Dennis Waterman for the theme tune of the ITV series Minder and became a Top 10 hit single in the United Kingdom during 1980. It also gained an Ivor Novello Award for Kenny. In 1983, he began to work with Alan Jay Lerner on a musical adaption of My Man Godfrey, but Lerner died before it could be completed. In 1985, after moving to WEA, Kenny charted in the UK with another theme song, "No Man's Land", from the ITV drama series Widows.
Since then Kenny has continued to record and release music periodically. His songs have been recorded by Barry Manilow, Johnny Mathis, Perry Como, Jack Jones, Marion Montgomery, Sacha Distel, James Last and Shirley Bassey, who recorded a song that he co-wrote with Lynsey de Paul, called "There's No Place Like London".
- "Where Are You?" (1967)
- "3 Weeks, 4 Days, 15 Hours" (1967)
- "Leave it to me" (1968)
- "New York, New York" - (1978) - UK No. 43
- "D-D-D-Dancing" (1979)
- "Fantasy" - (1980) - No. 34
- "The Other Woman, The Other Man" - (1984) - No. 69
- "No Man's Land" - (1985) - No. 56
- Living On Music - (1980)
- Made It Through The Rain - (1979) - No. 19
- City Living" (1981)
- The music of Gerard Kenny (1984)
- All For A Dream (1984)
- Play Me Some Porter Please (1992)
- The Time Between Time (1994)
- An Evening With Gerard Kenny Live (1995)
- The Best of... The Singles (1998)
- Coming Home (2005)