A major influence on improvisational theatre, Del applied his ingenuity and zest for experience in a variety of arenas. He participated in drama at MHS before graduating in December of his senior year. He attended classes at Kansas State and became a member of the Compass Players in St Louis at age 23. The cast moved to Chicago in 1959 to form Second City; but instead, Close moved to New York where he performed stand up comedy, worked with the classic beatnik satire album How to Speak Hipand in the musical revue The Nervous Set. In 1960, he moved to Chicago to perform and direct with Second City.
He left Chicago in 1965 to become one of the founders of the San Francisco comedy troupe, The Committee, where he stayed for five years.
Back in Chicago in 1970 as Second City director until 1982, he co-founded Improv Olympics in 1983 with partner Charna Halpern, where he developed the method for creating comic improvisations called ’The Harold’. With his teaching, he served as a mentor to many famous actors and comedians, such as John Belushi, Bill Murray, John Candy, Gilda Radner, Shelly Long, Chris Farley and many more. Saturday Night Live lives with the influence of his students. He also appeared in TV and movies, including Ferris Bueller’s Day Off and The Untouchables, and won the Joseph Jefferson award in 1985 for his performance in Hamlet. He died in 1999 at age 64. Leaving no survivors, he willed his skull for a final performance as Yorick in Hamlet.