D. L. (Donald Lee) Coburn was born on August 4, 1938, in East Baltimore, Maryland, to Guy Dabney and Ruth Margaret Somers Coburn. East Baltimore is an impoverished neighborhood, and Coburn's childhood was made the more difficult by his parents' divorce when he was only two. He served in the U.S. Navy from 1958 to 1960, right after graduating from high school. Coburn operated a one-person advertising agency in Baltimore from 1965 to 1968 and then worked for the Stanford Advertising Agency in Dallas, Texas. He married Marsha Woodruff Maher in 1975 and has two children, Donn and Kimberly, from a previous marriage, to Nazle Joyce French (1964–1971).
When he was thirty years old, Coburn began writing short stories for his own gratification and discovered that he had a talent for dialogue. After seeing Thomas Troupe's one-act play Diary of a Madman (adapted from the work of the Russian writer Nikolay Gogol), he decided to try playwriting. It took him several years to put pen to paper, and after only eight pages, he put aside his first attempt, The Gin Game, for two more years. At the urging of his young son, he finally went back to the project and finished the play in four months. Amazingly, the play progressed from a small Los Angeles theater to Broadway in little more than a year's time and earned Coburn a Pulitzer Prize and a Tony nomination for Best Play in 1978.
Other plays written by Coburn include Bluewater Cottage (1979), Guy (1983), Noble Adjustment (1985), Return to Blue Fin (1991), Fear of Darkness (1995), Firebrand (1997), and The Cause (1998). They have not gained sufficient popularity to warrant publication and are therefore not readily accessible to the reading public. In addition, Coburn has written television series pilots for two major networks and several screenplays, including Flights of Angels (1987), A Virgin Year (1991), and Legal Access (1994).