Callender competed in the 1988 Summer Olympics. He represented England and competed in the 100 metres and won a silver medal in the 4 x 100 metres relay event, at the 1986 Commonwealth Games in Edinburgh, Scotland. Four years later he represented England and won a gold medal in the 4 x 100 metres relay event with John Regis, Marcus Adam, Linford Christie and Tony Jarrett (heat runner), at the 1990 Commonwealth Games in Auckland, New Zealand. In the 1989 IAAF World Cup, his team won second place in the 4 x 100 m relay.