From his Wikipedia: James Edward "Jimmy" McGrory (26 April 1904 – 20 October 1982) was a Scottish International football player, who played for Celtic and Clydebank and then went on to manage Kilmarnock, before returning to Celtic after the end of the Second World War, to manage them.
He is the all-time leading goalscorer in top-flight British football with a total of 485 goals (408 Scottish League/77 Scottish Cup), he also scored 53 goals in secondary cup competitions, 6 goals for the Scotland international side and another 6 goals for the Scottish League XI. McGrory is a legendary figure within Celtic's history, he is their top scorer of all time, with 469 goals in 448 games and holds their record for the most goals in a season, with 57 League and Scottish Cup goals from 39 games, in season 1926–27. He has also notched up a British top-flight record of 55 hat-tricks, 48 coming in League games and 7 from Scottish Cup ties. It could be argued he in fact scored 56, as he hit 8 goals in a Scottish League game against Dunfermline in 1928, also a British top-flight record.
He was at Celtic for 15 years between 1922 and 1937, although he did spend the majority of the 1923–24 season on loan at fellow 1st Division side Clydebank. After a spell managing Kilmarnock from December 1937 to July 1945, he became Celtic manager, where he remained for just under 20 years, until March 1965 when he was succeed by Jock Stein.
Even although he was only 5 ft 6ins, he was renowned for his prowess and ability from headers. His trademark was an almost horizontal, bullet header, which he performed and scored regularly from and which earned him his nicknames, of the "Human Torpedo" and the "Mermaid".
McGrory was allowed to leave Celtic in December 1937 to become the first full-time manager of Kilmarnock, on the condition that he retire from playing. Kilmarnock were struggling in the league, and lost their first two games under McGrory; a humiliating 9–1 rout at the hands of Celtic in his debut as manager and a 4–0 loss to Hibernian. However, the team's form improved and they went on a run of losing only once in a dozen games, and eventually managed to stay up. He also led Kilmarnock to the Scottish Cup Final, knocking both Celtic and Rangers out en route. The final took place on 23 April 1938 between Kilmarnock and East Fife, finishing in a 1–1 draw. The replay was held four days later, Kilmarnock losing 2–4.
Kilmarnock improved further in McGrory's first full season as manager, finishing in a comfortable mid-table position in the league at the end of 1938–39. They weren't able to replicate the previous season's cup form however, going out of the Scottish Cup in the second round to Hibernian. Hopes that McGrory's side of efficient journeyman and enthusiastic youngsters could progress further were quashed by Britain's declaration of war against Germany in September 1939. The Scottish League was abandoned and regional competitions organised in their place to minimise travelling across the country during wartime. Kilmarnock's ground, Rugby Park, was then requisitioned by the army in the summer of 1940 as a fuel depot. The combination of losing their ground and players being conscripted resulted in Kilmarnock stopping playing football altogether. McGrory was kept on officially as manager, but had virtually nothing to do. During this time he found work as chief storeman at a munitions factory in Ayrshire and he also joined the Home Guard.
Kilmarnock finally returned to playing football again in the summer of 1944, although they had to play their home games at a nearby junior team's ground as Rugby Park was still being used by the army. Eventually their ground was returned to them in April 1945 and the club joined the Southern League for the forthcoming season. However, in July 1945 a Glasgow newspaper reported that McGrory would "make a sensational move soon." He himself later confirmed that Tom White, the Celtic chairman, had telephoned to arrange a meeting. McGrory duly travelled to Glasgow to speak with him, and was offered the job as manager of Celtic.