Here are some of his notable works:
Screenwriting:
* The Color Purple (1985), nominated for 11 Academy Awards, including Best Picture
* The Age of Innocence (1993)
* The Birdcage (1996)
* The Secret Life of Bees (2008)
* The Help (2011)
* The Girl on the Train (2016)
Playwriting:
* The Red Cross (1982)
* The House of Blue Leaves (1986), which won a Tony Award for Best Play
* The Queen's Gambit (2002)
* The Secret Garden (2009)
Therefore, while William August has a significant presence in the film and television world, it's primarily through his writing rather than acting.