[3] Playing as an outside left, he had a dream debut, scoring both of Celtic's goals in a 2–0 victory over Partick Thistle in the final league match of the 1931–32 season.
[4][5][6] MacDonald didn't fully break into the team on a regular basis until the departure of Willie Buchan to Blackpool in November 1937.
[7] The outbreak of the Second World War in September 1939 saw competitive football suspended for the duration of the conflict, but MacDonald remained with Celtic, making 199 wartime appearances (18 goals) before the official leagues and cups resumed in 1946.
[4] MacDonald departed Celtic after the war, having made 156 appearances in major competitions and scored 38 goals during his time with the club.
[9] Manager Harry Curtis played him as an inside forward, but a broken jaw hampered his progress and the Bees were relegated to the Second Division at the end of the 1946–47 season.
[15] He instantly turned around the club's fortunes, using a largely home-grown squad to push for promotion to the Second Division during the season,[15] though an injury to Len Newcombe would ultimately contribute to a second-place finish.
[3] The Brentford board's decision to shrink the playing squad (which included selling prolific twin forwards Jim Towers and George Francis) and to retain a number of players on a part-time basis contributed to the club's relegation at the end of the 1961–62 season.
[3] New chairman Jack Dunnett pumped money into the club in 1961 and MacDonald's signings of Johnny Brooks, John Dick and Billy McAdams in 1962 saw Brentford win the 1962–63 Fourth Division title at a canter.
[3] MacDonald briefly managed the Scotland team on a caretaker basis in late 1966 and presided over two 1966–67 British Home Championship matches: a 1–1 draw with Wales and a 2–1 victory over Northern Ireland.