McNicol was a competitive campaigner in the South African Championships during the late '60s early 70s.
He was second in the 1969 SA Championship driving a Lola T142 Formula 5000 car. The SA Championship of the time allowed a "free for all" of F1, F2 and F5000 cars. The Championship was won by John Love's Lotus 49 that year.
Later John McNicol graduated to a McLaren M10B and performed creditably against the pure F1 cars like Love's Surtees TS9 and March 701 , the Lotus 72 of Dave Charlton, and various Lotus 49, Brabham BT20's and BT24's. He was 4th in the 1972 Championship.
He then raced the Scuderia Scribante March 721 in 1973 and 1974 and picked up some podium placings.
He was entered to drive a Lotus 72 in the 1974 SAGP but did not start.
He was murdered by intruders at his smallholding near Johannesburg in July of 2001.