Johnson was a 6'10", 240 lb (110 kg) center who played 761 games for four teams during his 10 seasons in the National Basketball Association.

[2] Johnson was selected with the 22nd pick of the second round of the 1978 NBA draft by the Portland Trail Blazers.

[2] He was acquired along with a 1984 third-round selection (48th overall–Georgia forward James Banks) by the Philadelphia 76ers from the Indiana Pacers for Russ Schoene, a 1983 first-rounder (23rd overall–Mitchell Wiggins) and a 1984 second-rounder (29th overall–Stuart Gray) on February 15, 1983.

[1] After his NBA playing days ended in 1988, Johnson extended his career overseas in Italy.

[1][2] In May 2007, Clemon Johnson was named interim head coach of the University of Alaska Fairbanks Nanooks men's basketball team.