|Full name||John Henderson Blackley|
|Date of birth||12 May 1948|
|Place of birth||Westquarter, Scotland|
|1979–1981||Preston North End||53||(0)|
|1972||Scottish League XI||1||(0)|
|* Senior club appearances and goals counted for the domestic league only|
Blackley made 279 appearances at centre-half for Hibernian and also represented Newcastle United, Preston North End and Hamilton Academical. He won seven Scottish international caps and represented his country in the 1974 FIFA World Cup, playing in the 2–0 win against Zaire.
Blackley began a managerial career with Hamilton in October 1981, while continuing his playing career. He left Hamilton in 1983 and became a player/coach at Hibs, his first senior club, and was then promoted to the manager's position at Easter Road in 1984. His final managerial role was at Cowdenbeath, which he left to become Gordon Wallace's assistant at Dundee.
Blackley has since worked at several clubs with Paul Sturrock, including St Johnstone, Dundee United, Plymouth Argyle twice, Sheffield Wednesday and Swindon Town. His brief has been to work specifically with the defenders, passing on the experience he accrued in his 17-year playing career. Blackley was part of a successful coaching trio alongside Paul Sturrock and Kevin Summerfield that saw them achieve four promotions in six seasons. Blackley and Summerfield left Plymouth in October 2009 after being advised their contracts, which were due to expire at the end of the 2009–10 season, were not going to be renewed.