Piven came to Chicago in 1954 and met Joyce Hiller at the University of Chicago. They were married a short time later. In the 1950s, the Pivens were two of the founding members of the Playwrights Theatre Club, along with Paul Sills and David Shepard. Playwrights featured such budding stars as Mike Nichols, Elaine May, Ed Asner and Barbara Harris.
In the mid-1950s, the Pivens moved to New York, where they studied with Uta Hagen. Piven played the leads in several New York Shakespeare Festival productions. He was also part of the Obie Award-winning cast of A House Remembered.
They returned to Chicago in 1967 to rejoin Sills, Sheldon Patinkin, Bernie Sahlins and Joyce Sloane in forming Second City Repertory and then Story Theatre. In 1972 they started the Piven Theatre Workshop, partly to supplement their incomes, and partly to have something for their children to do after school. As Piven liked to point out, many of those children went on to fame and fortune.
Some of Piven's favorite roles include: The Man in 605, for which he received the Joseph Jefferson Award for best actor, the Piven Theatre Workshop/Famous Door production of The Shoemakers, directed by Shira, Victory Garden's production of The Value of Names with Shelley Berman, This Old Man Came Rolling Home and The Sunshine Boys at the National Jewish Theatre, Bob Falls’ Hamlet (starring Byrne's then-student Aidan Quinn) and the Workshop's futuristic production of Macbeth.
Piven also starred as the river boat captain in the Uncle Ben's rice commercials in the 1970s, and many television appearances. He died of lung cancer.
His son is actor Jeremy Piven.