Born in Wausau, Wisconsin in 1938, Warren was exposed to music and to the piano at an early age. His father Lawrence was a pianist and teacher and a close friend to other pianists, among them the Russian virtuoso Joseph Lhevinne, who actually gave Warren his very first training at the keyboard. At the age of five, Warren's family relocated to New York City where Warren immediately began serious study of the classical piano literature with well-known pianists Sascha Gorodonitzki, Miklos Schwalb and Herbert Stessin, as well as with his father.
In 1957, following his father's untimely death, Warren left music behind for several years while he majored in organic chemistry and physics at the University of Chicago. While living in this city rich in the tradition of jazz and blues, he once again became entranced with music -- this time with the fresh and exciting jazz improvisations of George Shearing, Oscar Peterson, Miles Davis, Wynton Kelly, and especially with the work of John Coltrane and Bill Evans. Soon thereafter, Warren joined the touring jazz sextet of saxophonist Paul Winter, and in 1962 the legendary John Hammond of Columbia Records brought the sextet to New York to record.
Warren has remained in the New York area ever since, recording and touring, as a jazz pianist, accompanist, sideman, arranger, producer and bandleader. He is also known as one of New York's finest musicians, having received the National Academy of Recording Arts and Science's (NARAS) Most Valuable Player Award for acoustic piano on four different occasions. Warren has toured and recorded with Jack Dejohnette, Gerry Mulligan, Jeremy Steig, Mike Mainieri, Gary McFarland, George Young and Kazumi Watanabe, among others, and he has accompanied such great singers as Donald Fagen, Carly Simon, Tim Hardin, Art Garfunkel, Richie Havens, Michael Franks, Patti Lupone, and Liza Minnelli.