After ending his stay with Blackburn Rovers' youth academy Toni returned to Finland to play for OLS Oulu.

His play with AC Oulu led to interest from Dutch Eredivisie club AZ Alkmaar who signed Kolehmainen in 2007.

In 2008, he was promoted to the first team squad by Louis van Gaal and made his debut in a 3-0 KNVB Cup victory over Achilles '29.

[4] Kolehmainen is currently based in Malta where he works as a director within the gaming industry at Rootz Ltd, often providing insights at events and conferences.

On 22 January 2012 Kolehmainen scored for Finland in his senior level debut, in a friendly match against Trinidad and Tobago.