Article in Huddinge AIS FriidrottRead the source grew up in Fullersta, according to Huddinge AIS’s retrospective account. The club also records that he took part in the Article in Huddinge AIS FriidrottRead the source athletics competition as a youngster in the late 1970s.
Mertzig played 6 senior seasons with Huddinge, from 1989/Article in WikipediaRead the source/95, before moving to Luleå. He spent 3 seasons there in Elitserien, from 1995/Article in WikipediaRead the source/98, appearing in the playoffs each year.
Mertzig also represented Sweden at the 1998 Article in WikipediaRead the source, playing in 4 games. Article in Swedish Ice Hockey AssociationRead the source historical register credits him with 37 senior internationals and 3 B-team internationals.