Trying to apply any kind of genre tag is a waste of time. Jim O'Rourke is all things and no particular thing. His albums range from pop to finger-picked solo guitar to ambient electronic, noise and beyond.
It's also worth checking out his earlier work as half of
Gastr Del Sol alongside
David Grubbs. Their output gives some good context to his later stuff. He was even a member of
Sonic Youth for a while!
Suggested Listening: I'm Happy, And I'm Singing, And A 1, 2, 3, 4 and
Halfway to a Three Way, for totally different reasons.