Jeff Daniels -- I Hit a Friggin' HOLE IN ONE!!!!

Jeff Daniels can die a happy man ... 'cause the "Newsroom" star smacked himself a HOLE IN ONE yesterday -- and, of course, he took photos to prove it.

Daniels was playing at the Polo Fields Golf Country Club in Ann Arbor, Michigan ... when he scored his numero uno -- and detailed the shot on Twitter:

"133yds. 8 iron into a stiff wind. Power Draw. No roll up and trickle in; a slam dunk. Two witnesses. #9."

Of course, Daniels was expected to follow the ultimate golf commandment after hitting a hole in 1 -- he's OBLIGATED to buy drinks for everyone in the clubhouse.

Don't worry ... he can afford it.