Peter grew up in Morristown, New Jersey and received a bachelors degree from The University of Michigan School of Music as a piano performance major. He competed in piano competitions before attending The Neighborhood Playhouse School of Theatre in New York City where he studied with Sanford Meisner, Phillip Gushee, and Richard Pinter. Soon, after two years of Meisner, he got a lead role in the Broadway show "On Your Toes" written and directed by the legendary George Abbott, then 95 years old. 2 years later he joined the Manhattan Rhythm Kings and toured with Tommy Tune before landing the Donald O'Connor part, Cosmo Brown, in "Singin' in the Rain" on Broadway at the Gershwin Theatre directed and choreographed by Twyla Tharp.After that he starred in "No Way to Treat a Lady" off-Broadway at the Hudson Guild, directed by Jack Hofsiss. Then he performed opposite Jack Wagner at Goodspeed in "Butterfly". "Animal Crackers" was next, playing Chico at the Huntington in Boston and the Alliance in Atlanta, followed by the role of Aldo in John Patrick Shanley's "Italian-American Reconciliation" at The Cleveland Playhouse. He moved to Los Angeles where his TV career started with "Murphy Brown". While in LA he starred in "Stardust" at the Wilshire Theatre with Toni Tenille and Sean Young and then went on to create roles in the American premiere of Andrew Lloyd Webber's "Sunset Boulevard" at the Shubert in LA starring Glenn Close and directed by Trevor Nunn. Susan Stroman and Hal Prince stole him from Sunset to play Frank in "Showboat" for them and after a year he was asked to play Chico Marx again, but this time in the first ever Broadway revival of "The Cocoanuts" in New York City. He got an actual 'sign' to change his name from Slutsker to Marx and did so in '98.Then came the role of Charlie Davenport in "Annie Get Your Gun" with Bernadette Peters and Tom Wopat at the Marquis Theatre. Peter stayed the entire 3 year run and then was asked to be in Nora Ephron's and Marvin Hamlisch's "Imaginary Friends" at The Barrymore Theatre directed by Jack O'Brien. After that he went into "42nd Street" playing Andy Lee opposite Tom Wopat again. Finally, Daniel Sullivan asked him to be in Elaine May's "After the Night and the Music" at The Biltmore.Becoming a single dad, Peter left the biz to be home nights and weekends with his two teenage daughters. He went into the world of IT staff augmentation but when his younger daughter goes off to college, he will consider returning to showbiz.