Kammala jumla mai zuwa: Mai tsere mai nasara a jami'a (ya karya lambar zinare ta Olympics Wyndham Halswelle mai shekaru 53 na Scotland na mita 300 a shekarar 1961), Campbell ya yi gasa ga tawagar Burtaniya a mita 200 da kuma
4 × 100 mita relay a wasannin Olympics na 1964 a Tokyo, kuma ya jagoranci tawagar Scotland a 1966 British Empire da Commonwealth Games a Kingston, Jamaica. Ya kuma zama kyaftin din kungiyar 'yan wasa ta Burtaniya a shekarar 1965 da 1966, kuma ya rike tarihin mita 100 na Burtaniya daga 1967 zuwa 1974. A wani lokaci an san shi da "fararen fata mafi sauri a duniya", yana gudu 100m a cikin 10.2 seconds sau biyu a cikin 1967. A cikin tserensa na 10.2 na farko ya doke O. J. Simpson, wanda a lokacin ya kasance mai son zama dan wasa.