Kalman was born in Mateszalka, Hungary into a prosperous middle-class family.
He moved to the United Kingdom at age 16 to study English, but switched to chemistry.
Initially, his father sent him an allowance to support him, but when Hungary joined the Axis Powers, he was cut off.
Thanks to his mother, he had trained to become a capable tennis player and made some money coaching during the weekends.
In 1968 he played his final singles tournament at the London Hard Court Championships on clay.