Debevec started shooting in 1971 and became a member of the Yugoslavian junior national team in 1979.

Debevec joined the Military Sport Squad of the Slovenian Army in 1991[2] and holds the rank of Warrant Officer.

He won gold at the 2000 Summer Olympics in Sydney, where he competed in the event 50 metre rifle three positions.

Latvian shooter Afanasijs Kuzmins is the only shooter with more Olympic appearances than Debevec; Kuzmins competed in his ninth games at the 2012 Summer Olympics, where Debevec competed for the eighth time.

He has won two world military championships in 300m three positions in 2006 and 300m rapid fire rifle in 2005 and 2008.