From Biography Magazine
STEVE MCQUEEN Born Terence Steven McQueen on March 24, 1930, in Beech Grove, Indiana. The ex Marine-turned-Icon-of-Cool played a gunfighter in The Magnificent Seven and a P.O.W. in The Great Escape. Clearly, McQueen, who died in 1980, had military blood coursing through his veins. Need proof? His 4th great-grandfather, Asa Thomson, who was born in 1764, tried to enlist as a soldier in Virginia during the American Revolution, but was too young. Rather than wait a bit, he hauled himself to North Carolina to join up. McQueen's 3rd great-grandfather, Capt. John W. Thomson, who commanded a Missouri militia, was shot by a sentinel at an encampment in Richmond, Missouri, in 1822. And the actor's 4th great grand-uncle, David Thomson, a Kentucky State senator from 1811 to 1820, served as a general in the War of 1812.
(thank you to Donna Redden for the information)