Heisler has grown up in a family of country doctors. He studied law, journalistics and behavioural science in Munich. 1970 he studied medicine in Freiburg. He was film assistant of Walter Frentz, who was camera-man of Leni Riefenstahl. At the Olympic Games in Munich 1972 he was personal assistent of IOC-Vice president David Cecil, 6. Marquess of Exeter.
In 1972 he founded the Audimax classics and jazz concerts Freiburg until the ZMF – Zeltmusik-Festival Freiburg (Tent Music Festival) was founded in 1983. Roncalli chief Bernhard Paul borrowed him tents and internationale stars drew hundreds of thousands visitors. After high losses in 2006 because of the football championship in Germany he changed to the board and others took over the organisation.
From 1986 thru 2021 he had an office as GP in Teningen.