The son of a miner, Busby was born in the village of Orbiston, near Glasgow. He played local football for Denny Hibs. At 17 he joined Manchester City, then played for Liverpool until the Second World War, when he served in the King's Liverpool Regiment and the Army Physical Training Corps.

After the war, Busby accepted the job at Old Trafford and built his first successful side. In 1948 they won the FA Cup for the first time, beating Blackpool 4-2 in the Final. In the League his side finished runners-up four times in five seasons, and finally clinched the championship in 1952. Busby's youth development policy began to pay dividends. United won the FA Youth Cup in its first five seasons from 1952-1957, with players who formed the nucleus of the senior side that became known as the Busby Babes. United won the championship in 1956 and 1957. They were on course for the first League and FA Cup Double of the century in 1957, but lost in the Cup Final to Aston Villa.

Against the will of the Football League, Busby took United into the European Cup in 1956 and reached the semi-final. A year later came the Munich air disaster. Busby was critically injured and on his recovery he was close to quitting football. He was persuaded to continue and began rebuilding the side. In 1963 he saw his side take the FA Cup, beating Leicester 3-1. The arrival of George Best helped Busby's third great side to the championship in 1967.