Yak was a legend as a stuntman and a stunt coordinator. He was smart and innovative in doing stunts. He had a lot of bit parts, almost always as the villian, in the really old '30s John Wayne cowoy flicks, where he does some hairy stunts and ridiculously incredible riding and mounting. It's said that over time, he broke every bone in his body, and I believe it. He was the first guy to master jumping from one galloping horse to another to take down a bad guy. From a distance you can't tell he's not John Wayne.
Yak was amazing.
Yakn was a great stunt man and double. In GONE WITH THE WIND he was used as a double for Clark Gable, and in one scene where he drives a wagon up to Scarlet, he looked so much like Clark they left the scene in the movie instead of re-shooting with Gable.
He was later the white renegade (along with a black former slave) who attack Scarlet out on Decatur Road.