[2] This form brought him to the attention of the national selectors, and he was selected to compete as England's only 400 m representative at the 2004 Commonwealth Youth Games, in Bendigo, Australia, where he won a bronze medal.

Seeking ways to fund his Olympic ambitions, Buck works part-time at a supermarket whilst juggling a heavy training schedule.

Buck was selected to represent Great Britain at the 2008 Summer Olympics in the 4 × 400 metres relay event but a virus interrupted his training and he never competed in Beijing with the squad.

[1] This boded well for the 2009 European Indoor Championships but he was disappointed with fifth place in the 400 m finals, finishing in 46.93 s.[6] However, he claimed the silver medal as part of Britain's 4 × 400 metres relay team with a time of 3:07.04.

In July 2015 Buck announced that he was retiring from athletics to pursue a career as an actor, after accepting a place on a master's degree course at Birmingham School of Acting commencing that September.

[8] Buck ran his final race in St Peter Port, Guernsey at the Intertrust Anniversary Games, winning ahead of current GB Junior Cameron Chalmers.