Born in North Carolina and raised in Washington, DC, Grizzard began his acting career in a production of "The Corn Is Green" at the Crossroads Theatre in Virginia in 1945, before working at the Arena Stage. He headed to NYC to study with Sanford Meisner and soon made his Broadway debut in "The Desperate Hours" (1955) playing Paul Newman's younger brother who joins in taking Karl Malden and his family hostage. The next year he won a Theatre World Award for his work in "The Happiest Millionaire", earned a Tony nomination for his turn in "The Disenchanted" and created the role of Nick in Edward Albee's "Who's Afraid of Virginia Woolf?" (1962). Grizzard went on to play numerous classical roles, including several at Minneapolis' Guthrie Theater, before returning to the Great White Way in a 1965 revival of "The Glass Menagerie". By 1970, he was playing Julius Rosenberg in Donald Freed's "Inquest" and two years later co-starred with Jason Robards in a revival of Clifford Odets' "The Country Girl". Throughout the 70s, he worked in plays by many of America's best writers including Arthur Miller ("The Creation of the World and Other Business" 1972), George S Kaufman and Edna Ferber (the 1975 revival of "The Royal Family") and Neil Simon ("California Suite" 1976). In 1986, Grizzard tackled the role of Tobias in Albee's "A Delicate Balance" at the Berkshire Theatre Festival and a decade later capped his long stage career with a Tony Award as Best Actor in the Broadway revival.
Despite his extensive stage credits, Grizzard managed to find occasional film and TV roles. Throughout the small screen's so-called 'Golden Age', he appeared in numerous anthology series and such prestigious offerings as "Teacher, Teacher", a 1969 NBC "Hallmark Hall of Fame" offering in which he was cast as the father of a retarded youth. His work alongside Henry Fonda in the live presentation of "The Oldest Living Graduate" (NBC, 1980), earned him a well-deserved Emmy Award. Grizzard has often played real-life figures in TV shows such as journalist Tom Wicker in "Attica" (ABC, 1980), John Siegenthaler in "Robert Kennedy and His Times" (CBS, 1985) and US President Jimmy Carter in "Iran: Days of Crisis" (TNT, 1991). More recently, he returned to his Southern roots in two CBS miniseries 1993's "Queen" and 1994's "Scarlett". Grizzard and Elaine Stritch (with whom he also co-starred in "A Delicate Balance") offered delicious comic turns as the battling parents of Jane Curtin in a 1997 episode of the NBC sitcom "3rd Rock From the Sun".