[2][3] McNichol graduated from junior footballer and apprentice motor mechanic in his native Scotland to a professional contract with English First Division club Newcastle United.

In 1958 he joined Crystal Palace, whom he captained to promotion from the Fourth Division, and finished his on-field career in the Southern League as player-manager of Tunbridge Wells Rangers.

During the Second World War, McNichol was called up to the Fleet Air Arm as a mechanic, but was able to play friendly matches for Inverness-based club Clachnacuddin.

[7] In his second season, he was part of the reserve team that won the Central League title,[9] but a disagreement over personal terms on his contract renewal – the Newcastle management felt a lower wage was justified because of the player's earnings outside the game[8] – prompted McNichol to seek first-team football elsewhere.

[10] The next year, McNichol played in all of Brighton's games, the only man so to do, and again finished as top scorer for the season, this time with 14 goals.

He scored 14 goals in the 1951–52 season as Brighton narrowly failed to mount a successful challenge to Plymouth Argyle for the title, "was again the star of the side",[12] and "was thought by many to be the most stylish inside-forward to play for the Albion".

[12] On his Chelsea debut away at Manchester United, McNichol found himself playing at right back after ten minutes when Sid Tickridge sustained an injury.

As they beat Charlton Athletic in March 1955 to "maintain their challenging position in the Championship", The Times' reporter described how "McNichol filled the role of general, and was instigator of many dangerous movements".

[2] While at Brighton, McNichol had worked in a local garage, wanting to keep up his skills in case injury put an early end to his football career.

He was expected to fill a role "similar to the one he has performed so well at Stamford Bridge – helping in the development of promising young forwards",[23] and was appointed captain.

A broken arm suffered in August 1961 forced McNichol to miss a Palace match for the first time in a three-and-a-half-year club career.

[3] McNichol remained in the South of England, spending four years as player-manager of Tunbridge Wells Rangers in the Southern League.

Having sold the newsagents, he returned to Crystal Palace to work in the commercial side of the game, where he was responsible for the establishment of weekly pools and bingo competitions as a means of raising funds for the club.

He described Chelsea's decision not to accept their invitation to participate in the inaugural season of the European Cup as his "one big disappointment", and "thought it was strange at the time", despite the national team selectors' preference for players plying their trade for Scottish clubs, that he was never chosen to represent his country.