After getting his first taste of refereeing at the tender age of 15, Martin Hansson took charge of his first game in the top tier of Swedish football in 1999. His international career began in 2001, with a debut in the UEFA European U-16 Championship, as well as a qualifying-round UEFA Champions League match between Sheriff Tiraspol and Anderlecht.

In 2003, he oversaw his first meeting of national teams (Estonia-Canada), and added another three UEFA Cup fixtures to his CV alongside a call-up for the FIFA U-17 World Cup in Finland in 2003, where he officiated in the Argentina-Spain semi-final.

In 2005, he refereed his first European qualifier for the FIFA World Cup™, as well as a group-stage UEFA Champions League match (Juventus-Rapid Vienna), later presiding over the Netherlands-Ukraine final of the UEFA European U-21 Championship.

A fireman and keen amateur hunter and fisherman, Hansson holds the record for the most appearances in a single FIFA U-20 World Cup tournament: in Canada 2007 he took charge of six games, including the match for third place between Austria and Chile.