He began his professional football career at the end of the
Second World War when he was signed by Belfast side
Glentoran. In
1949, Barnsley F.C. paid £6,000 to transfer him to England, and two years later
Aston Villa bought him for £15,000. He played 155 times for Villa, captaining the side on many occasions.
He grew disenchanted with the club and the way training was conducted, becoming one of the first to propose that players should train with a ball as opposed to merely undertaking physical exercise. In
1954 he was bought by Spurs for the huge fee of £30,000, and during his ten years at
White Hart Lane he made 337 league appearances.
The highlight of his time at Spurs came with the 1960-61 season. With Blanchflower as captain Spurs won their first 11 games, still a record for the top flight of English football and eventually ran out as league champions by 8 points. They then beat
Leicester City in the final of the
FA Cup to become the first team in the 20th century to win the league and cup double not achieved since Aston Villa in
1897.
In
1962 he again captained Spurs to victory in the FA Cup, only narrowly missing out on a second double when they finished a close third in the league behind
Ipswich Town and
Burnley, and in
1963 he captained his side to victory over
Atlético Madrid in the final of the
European Cup Winners' Cup.
Between 1949 and 1963, he earned 56 caps for
Northern Ireland, often playing alongside his brother
Jackie, and in
1958 captained his country when they reached the quarter-finals of the
World Cup.