He studied philosophy at the Charles University in Prague, and later obtained a diploma from the British Association of Industrial Editors.

In 1937, Kelen and Miklos Szabados embarked on a two-year table tennis exhibition tour of the Far East and South America.

They won the doubles tournament at the Australian national championships, and Szabados defeated Kelen in the singles final.

A member of the 66th Australian Infantry Battalion (Intelligence), he served in New Guinea, Halmahera, North Borneo, and finally as part of the British Commonwealth Occupation Force in Japan.

[1] Back in Australia, Kelen worked for the Australian Broadcasting Corporation (ABC) as an author and journalist, writing documentaries and features.