Barker also represented Vic Metro (Metropolitan Victoria) in the Teal Cup and was named at centre half forward for the Victorian Under 18 All-Star team.

Barkers' form at Under 18 level attracted plenty of interest from AFL club scouts.

In the 1992 AFL Draft John Barker was selected at pick 25 by the Fitzroy Football Club.

[2] Barker did not play a senior game for Fitzroy in 1993 and missed most of the season due to back and hamstring injuries.

At the end of the season Barker and teammate Nathan Chapman were traded to Hawthorn in exchange for Brad Scott.

Barker kicked 4 goals and took some clean one-grab marks to help the hawks come from behind to beat the Brisbane Lions in a thriller (Hawthorn 16 14 110 def.

[8] 2006 would be John Barkers final year as an AFL footballer and he could just manage 7 games due to on-going shoulder and hamstring injuries.

In the week leading up to round 20 of the '06 season Barker announced his retirement, saying his body could no longer stand up to AFL football.