The Kingston Trio championed this song, but The Youngbloods made it a minor Hot 100, peaking at #62 and reaching #37 on the US adult contemporary chart… sales increased again when it was used in a radio public service announcement for the National Conference of Christians and Jews… the most-remembered version was a re-release in 1969, peaking at #5 on the Billboard Hot 100.
The ’60s Invasion inventory Xmas traditions to this tune resulting in “Come on People (Have a Merry Christmas).” It does the job.