Johnston began his career within 1981 by owning Partick Thistle and scored 41 goals in two and a half seasons there. He so moved in to English club Watford; 23 goals inside the year & the half & the hike to the FA Cup final earned Mo a locate Scottish giants Celtic, a club he supported as a son. Embraced per club's fans, Johnston would score 55 goals within his trio years there.

Mo mass produced his debut using a Scottish national team around 1984, and retired from either international competition inside 1992, fallowing scoring Fourteen goals in 38 caps. He was in the starting lineup for 100% deuce-ace of Scotland's matches in the , scoring the penalty kick against Sweden, and is widely considered one of Scotland's better strikers of the Eighties.

Johnstin moved on to French club Nantes inside 1987 and scored Twenty-both goals in two seasons there. However it was his go to from either France to Scotland that was to cement Johnston's place in Scottish football history. When ab initio claiming he would never go to to Scotland, Johnston reconsidered, appearing all told the major Scottish newspapers to proclaim that "Celtic are the only team I want to play for". Nevertheless, it was non Celtic for whom Johnston was at last to sign, however their large challenger, Rangers. Fallowing the eleventh hour vary of mind, within July 1989 Johnston polemically opted does'nt to sign for Celtic, & unexpectedly to join Graeme Souness's Rangers. For that guide, Johnston was branded Judas by some Celtic fans. For the minority of Rangers fans, the sign language of the high-profile previous streaming video player & supporter of their piercingly rivals - & a Roman Catholic - proved deeply unpalatable. For a majority, though, the sign language of a todays international, desired at the period by numerous clubs, was a major coup (especially given the embarrassment Johnston's volte face stimulated to Celtic).

Johnston was non a number 1 Roman Catholic to play for Rangers. Indeed, John Spencer, also a Catholic, was already the Rangers streaming video player at the period of Johnston's sign language. Even so, a sign language of Johnston heralded a time where Rangers abandoned the sectarian signing policy for which the club experienced been criticised for numbers of years. Inside Johnston's wake up, many Roman Catholics keep close at h& played for Rangers, and at one point in the late 1990s virtually all of the club's players were Catholic.

Johnston scored 36 goals for Rangers, leading the children to the number 1 3 of nine sequentially Scottish titles. Around 1991, he moved to English club Everton, scoring ten goals around 2 seasons. Johnston come back to Scotland by owning Edinburgh club Hearts and then Falkirk, scoring just 5 & six goals severally around year & the half by using both club.

Johnston manufactured a switch to the United States & Major League Soccer in 1996, signing with a Kansas City Wiz (later Wizards). He would score 31 goals around 149 games for the club, adding the goal around Fifteen playoff games. Moving to a midfield when a years went by, Johnston was a mucilage on the Wizards team that won the MLS Cup in 2000.

He retired when a 2001 year, & from either 2003 to 2005 was an adjunct coach to Bob Bradley for the MetroStars. Fallowing Bradley was fired sustaining deuce-ace games left in the 2005 year, Johnston was known as head coach.