Braithwaite was a member of the British team which set a world indoor record for the rarely contested 4×200 metres relay on 3 March 1991 in Glasgow.

Braithwaite and his teammates Linford Christie, Ade Mafe and John Regis ran a time of 1:22.11, which has yet to be bettered.

Braithwaite won a bronze medal in the 4×100 metres relay event at the 1991 World Athletics Championships in Tokyo (together with Tony Jarrett, John Regis and Linford Christie).

He repeated this achievement at the 1997 World Athletics Championships in Athens (together with Darren Campbell, Douglas Walker and Julian Golding).

Braithwaite now teaches physical education at Lammas School and Sports College in Leyton, and coaches the likes of Jordon Roberts.