While attending high school in England, David Threlfall was encouraged by two separate teachers to try his hand at stage acting. After graduation he quickly enrolled at the Manchester Metropolitan School of Theatre, and thus a passion was born. Some of the plays Threlfall appeared in during this time include the dramas "The Sons of Light" and "A&R," both produced by the prestigious Royal Shakespeare Company in London. By the late 1970s, however, Threlfall began appearing in television dramas such as "Here I Stand" and "BBC2 Playhouse," as well as the 1982 mini-series "The Life and Adventures of Nicholas Nickleby." Throughout the 1980s, Threlfall appeared almost exclusively in British TV shows and made-for-TV movies, including the drama "Objects of Affection," the comedy "Lenny Henry Tonite," and the 1983 television adaptation of Shakespeare's "King Lear," in which he starred alongside the legendary Laurence Olivier. He received rave reviews for his role as Prince Charles in the 1993 made-for-TV movie "Diana: Her True Story," and followed that up by playing another historical role, this time as Charles' father, Prince Phillip, in 2005's "The Queen's Sister." In 2004, he landed his most notable role as Frank Gallagher, the patriarch of a dysfunctional family in a fictional working-class neighborhood of Manchester, England, on the British comedic drama "Shameless."