Marc McClure
From Futurepedia, the Back to the Future Wiki
Marc McClure (born March 31, 1957) is an American actor who played the role of Dave McFly in Back to the Future. He is also well known for portraying Jimmy Olsen in Superman (1978) and its three sequels, as well as Supergirl. Along with Wendie Jo Sperber, McClure had been cast by Robert Zemeckis and Bob Gale in two earlier films, I Wanna Hold Your Hand (1978) and Used Cars (1980). Coincidentally, McClure had played characters named "Dubois" in both films.
He reprised the character of Dave McFly in Back to the Future Part II, but the scene (in which Marty encounters a drunken Dave in front of Biff's Pleasure Palace in the alternate 1985A) was cut. He was brought back for Back to the Future Part III, where he was seen again as Marty's older brother Dave.
