Medoff was born on 18 March 1940 in Mount Carmel, Illinois, to a Jewish family, the son of Thelma Irene, a psychologist, and Lawrence R. Medoff, a physician. He was raised in Miami Beach. In 1967, while working as an instructor at the Capitol Radio Engineering Institute in Washington, D.C., he wrote his first play, The Wager. His first play to be staged in New York City was When You Comin' Back, Red Ryder?, which won him the 1974 Drama Desk and Obie Awards for Outstanding New Playwright.
Medoff's big breakthrough and most famous work was 1979's Children of a Lesser God, which won him the Tony, Drama Desk, and Laurence Olivier Awards for Best Play. Medoff was back on Broadway again with the staging of his play Prymate in 2005. Medoff's screen credits include adaptations of his plays Red Ryder and Children of a Lesser God, for which he was nominated for an Oscar, BAFTA, and Writers Guild of America Award, Clara's Heart, and City of Joy. In 2000, he produced and directed the documentary Who Fly on Angels’ Wings, about a mobile pediatric unit traveling through the under-served regions of southern New Mexico, and the following year he directed the feature film Children on Their Birthdays, based on the short story by Truman Capote.
Teaching
Medoff was co-founder of the American Southwest Theatre Company and head of the Department of Theatre Arts for nine years at New Mexico State University, where he was a professor for a total of twenty-seven years and taught Screenwriting and Acting for Film, Short Film Production, and Film Directing and Producing. He was also the Creative Director of the Creative Media Institute at NMSU, the film department at the university. The theater department is still the American Southwest Theater Company. For one semester a year between 2003–06, he worked at Florida State University as a Reynolds Eminent Scholar in the School of Theatre. In the spring semester of 2008 he joined the faculty of the University of Houston School of Theatre and Dance as Distinguished Lecturer. He was the winner of the Kennedy Center Medallion for Excellence in Education and Artistic Achievement, given periodically to professionals in theater who also teach and mentor students.
Medoff was married to second wife Stephanie Thorne from 1972 until his death in 2019; they had three daughters. In April 2019, he entered hospice care after battling cancer in his later years and suffering a fall. He died on April 23, 2019, from complications at age 79.
Medoff's theatre directing credits include Waiting for Godot, The Effect of Gamma Rays on Man-in-the-Moon Marigolds, Jacques Brel is Alive and Well and Living in Paris, One Flew Over the Cuckoo's Nest, Equus, and Hot L Baltimore. As an actor, he has appeared in the plays Marat/Sade, Black Comedy/White Lies, and Old Times, among others, and the films The Twilight of the Golds, Santa Fe, Homage, Red Ryder, and Clara's Heart.