During his club career, Mordt played for Kolbotn Illinois, Vålerenga IF, IFK Göteborg, Saskatchewan Brann and Drøbak/Frogn Illinois. In 1986, at only 21 years of age, Mordt missed the vital penalty kick in the 1985-1986 European Cup semi final against Football Club Barcelona, resulting in the Catalans progressing to the final stage of the tournament at the expense of IFK Göteborg. He also amassed 31 caps for the Norwegian national team, scoring 1 goal.