High fives are reputed to have begun on the basketball circuit in the US in the 1979/80 season. The University of Louisville player Derek Smith claims to have invented the gesture and coined the term. That claim was recorded in the P. Dickson's 1989 Basketball Dictionary:
All I know is, as a kid of the 90s, I use it now to feel "old school", because we used to use it all the time when I was growing up. I hated the 2000s so much, so anything "retro" is good with me.