His early progress led to a proposed transfer to Leeds United in November 1971, but this collapsed when a medical examination discovered a heart condition.
[12][13] He was eventually transfer listed by then West Brom coach Don Howe, alongside favourites Len Cantello and Jeff Astle, in April 1974.
[14] In the 1985 League Cup Final, Hartford's shot was deflected by Sunderland's Gordon Chisholm for the only goal of the match.
[19] He became a regular in the international side in 1977, as Scotland defeated Czechoslovakia and Wales to qualify for the 1978 World Cup in Argentina.
[20] Brian Glanville, in his frequently updated The Story of the World Cup, wrote "The Scots had an abundance of fine midfield players at a time when most other countries looked for them desperately; Bruce Rioch, Don Masson, Asa Hartford, Archie Gemmill, Lou Macari, Graeme Souness".
His side lost 3–1 to Peru, drew 1–1 with Iran and defeated eventual runners-up Netherlands 3–2,[20][21] which meant that Ally MacLeod's team exited the competition after the first round.
Hartford's international career came to an end after the 1982 World Cup, where he recorded his 50th and final cap for Scotland in the game against Brazil.
[10] He subsequently joined ex-international teammates Kenny Dalglish (at Blackburn Rovers), Joe Jordan and Lou Macari (at Stoke City where he spent four matches as caretaker manager) in various coaching/managerial roles.
On 29 June 2007 it was announced that he had been appointed assistant manager at Macclesfield Town but both he and Ian Brightwell were sacked in February 2008 to be replaced by Keith Alexander.