Michael Brown, left, keyboardist for the “baroque rock” band the Left Banke, co-wrote the 1966 hit song “Walk Away Renee.” (Michael Ochs Archives)

Michael Brown, a songwriter and keyboardist for the “baroque rock” band the Left Banke who co-wrote its 1966 pop hit “Walk Away Renee,” died March 19 at his home in Englewood, N.J. He was 65.

The cause was a heart ailment, a family spokeswoman said.

Mr. Brown was born Michael Lookofsky and grew up in Brooklyn. He was a classically trained keyboardist, and his father ran a New York music studio where the Left Banke recorded.

The quintet, which used strings and classical motifs in its compositions, formed in 1965 and featured Mr. Brown’s father playing violin on its best-known song. “Walk Away Renee” was reportedly inspired by the teenaged Mr. Brown’s silent, unrequited love for the girlfriend of a bandmate.

It was the Left Banke’s biggest hit and rose to No. 5 on the Billboard Hot 100 chart. The Four Tops also had a popular single with the song. Mr. Brown also composed “Pretty Ballerina,” which rose to No. 15 on the Billboard Hot 100 chart before the band split up.

Mr. Brown, who reunited periodically with his former Left Banke bandmates, later helped found the group Stories but parted ways before it had a chart-topping hit with “Brother Louie” in 1973. He subsequently played with the Beckies.

Survivors include his wife, Yvonne Vitale, and twin sons.

An earlier version of this article incorrectly reported that the Left Banke’s “Walk Away Renee” rose to No. 14 on the Billboard Hot 100 chart. It rose to No. 5.