Background
Hadler was born in Bergen as the son of Aage Hadler and Ruth Karin Rosendahl.
Hadler was born in Bergen as the son of Aage Hadler and Ruth Karin Rosendahl.
He studied at the University of Oslo, and graduated as candidate.real.
His first sports club was Bergens Turnforening. degree in 1970. Hadler had his breakthrough in competitive orienteering in 1966. He participated at the very first World Orienteering Championships, which were held in Fiskars, Finland, 2 and 3 October.
The individual course had 11 controls over 14.1 kilometres.
Anders Morelius from Sweden placed third in the individual race. Hadler married fellow orienteer Ingrid Thoresen 17 August 1968.
They both qualified for the World Championships, which were held in Linköping, Sweden, 28 and 29 September. In 1970 the World Championships where held in Friedrichroda, in the Democratic Republic of Germany, from 27 to 29 September.
In 1970 Hadler published the book På tvers av stiene.
The 1972 the World Championships where held in Staré Splavy, Czechoslovakia, from 14 to 16 September. Hadler was appointed as a research worker at the institution Fondet for markedsog distribusjonsforskning in 1971, and served as manager from 1976 to 1986. He was appointed at the Norwegian Mapping Authority from 1986.
He is currently serving as a communication advisor.
He is honorary member of the sports club Illinois i BUL.