In all likelihood we will never know - it appears to have spontaneously developed in a few places at roughly the same time. There are a few urban myths also floating around to confuse the scene. Another factor to consider is the ‘low five’ predated it’s high-flying cousin by a good margin, so people were acquainted with this idea of smacking palms together to communicate. Moving the gesture up top would have been a relatively smaller innovation that could have occurred to more than one individual. The two most likely candidates for 'inventor' are Glenn Burke and/or Derek Smith.

The earliest possible appearance belongs to Glenn Burke. Obviously a High-Five can't be done alone; Burke's celebratory partner was Dusty Baker. In 1977 both men were playing baseball for the LA Dodgers. On October 2nd Dusty Baker goes yard and racks up his 30th homerun of the season. Burke is on-deck and as Baker rounds 3rd and heads home, Burke raises way up – really arching back and Baker just reaches up and smacks his hand. There it is – the first high-five right?... well maybe, there’s some confusion; the game wasn’t televised so there’s no hard evidence. People there that day don’t recall if this was unique – like the first time they’d ever seen it or not. (to further cloud the issue Burke was gay so there’s some sentiment that others might be purposefully obscuring his role out of bigotry).

If we want hard evidence we can look at the case for Derek Smith, a member of the University of Louisville basketball team. Again we see the low-five being used, but at some point during the 1978-1979 season a teammate (Wiley Brown) of Smith’s goes to get a low five and Smith escalates it by saying, “No – up high”. This seems to suit the ballers’ style and becomes common. During the 1980 NCAA finals Brown cashes a jumper, draws a foul and goes to get some skin from Brown: “SMACK” – the TV announcer has seen this before because he knows the name for the gesture (kind of) and cuts loose with “Mr. Brown came to play! And they’re giving him the high-five handshake! High five!”

So pick the story that resonates most with you and run with it 

Full disclosure: This post was mostly ripped off from NPR’s Jon Mooallem’s article for ESPN. There’s also a fantastic Radio Lab covering the research done for the story.