Green’s Dictionary of Slang

(US) to act decisively, daringly, in an aggressive manner; often in ironic use.

1972		J. Wambaugh Blue Knight 161: Nothing I like better than John Wayne-ing a goddam door.
1977		L. Heinemann Close Quarters (1987) 38: Why, you can even John Wayne it and pull the son of a bitch [i.e. a grenade pin] with your fucken eyetooth.
2004		B. C. Works at military.com 19 Apr. 🌐 In the Vietnam era, we used to sneer at actors and soldiers when they were ‘John Wayne-ing it’ and taking risks for the wrong reasons.
2008		G. Pelecanos Way Home (2009) 68: John Wayned him up with instructions to never show weakness and ‘step aside for no man’.