Johnston also played for Hakoah Sydney, West Bromwich Albion, Vancouver Whitecaps, Birmingham City, Heart of Midlothian, South China AA and East Fife.

Born in Glasgow but raised in Fife and known by the nickname 'Bud',[6][7][8][9][10] Johnston began his career at local Junior club Lochore Welfare, also signing schoolboy forms with Rangers.

[11] Two months later, following injury to the established outside left Davie Wilson, Johnston was named in the side for the final of that competition and received his first winner's medal after a 2–1 Old Firm victory over Celtic.

The 1970 Scottish League Cup Final went Rangers' way 1–0 over the familiar opponents, Johnston providing the cross for the winning goal,[10][28] but he was fined afterwards by manager Willie Waddell for showboating (sitting on the ball), which supposedly brought shame on the club.

[32] On 1st December 1972 Johnston joined a struggling West Bromwich Albion[33] who were 1 point above England's top tier[34] relegation positions.

[12][7] After Scotland's opening game against Peru in the 1978 World Cup in Argentina, Johnston tested positive for a banned stimulant contained in Reactivan, a medication prescribed for his hay fever.

[45][12] Johnston was a key member of the 1979 NASL champion Vancouver Whitecaps alongside the likes of English World Cup winner Alan Ball, helping them defeat the New York Cosmos in the semi-final, and then the Tampa Bay Rowdies 2–1 in Soccer Bowl '79.

[11] During a game at Ibrox that year, Aberdeen player John McMaster had to be given the kiss of life after Johnston stamped on his throat,[7][46][12] often listed as one of the reasons for the development of the rivalry between the clubs.

[11] He then had a spell at Hearts under another old Gers colleague, Alex MacDonald, where he was sanctioned by the SFA for apparently headbutting Celtic's David Provan and clashing with their manager Billy McNeill (a former on-field adversary), and later for commenting on the incident in a newspaper.

[12] In 2004 Johnston was named as one of West Bromwich Albion's 16 greatest players, in a poll organised as part of the club's 125th anniversary celebrations.