Mo Johnston has had a significant career in football as both a player and a coach, known for his impactful performances across several major leagues and his tenure in Major League Soccer. After establishing himself as a formidable forward with 41 goals in two and a half seasons for Partick Thistle starting in 1981, Mo Johnston went on to achieve significant success across major football leagues. His early success at Partick Thistle, where his talent as a lively and instinctive striker quickly became apparent, led to a move to English club Watford in November 1983. At Watford, Johnston scored 23 league goals and played a crucial role in the team reaching their first-ever FA Cup final in 1984, solidifying his reputation as a prolific goalscorer.
Johnston returned to Scotland in 1984, joining Celtic FC where he continued his impactful career, netting 52 goals in 99 league appearances. During this period, he secured the Scottish Cup in 1985 and the Scottish league championship in 1986. Following his successful tenure in Scotland, Johnston moved to French football, playing for Nantes from 1987 to 1989, where he contributed 22 goals over two seasons. A pivotal turn in his career occurred in 1989 when he joined Rangers, securing two Scottish league titles in 1990 and 1991, and scoring 46 goals in 100 appearances.
Additionally, he was recognized as a Sporting Legend by Sporting Kansas City, celebrating his significant impact during his MLS playing career.