Bak began his career at Excelsior Rotterdam. After the end of World War II Bak went on for some years after Indonesia. After his return to the Netherlands he joined first at the Rotterdam FC. From 1955 to 1962, he was then in the squad from Feyenoord in the Dutch Eredivisie. With Feyenoord midfielder in 1961 and 1962, twice in a row of Dutch national champion. Overall Bak ran for the club 156 times on which 133 times in league games, scoring 11 goals.
He also denied on June 6, 1956 international for the Dutch football team in Amsterdam against the Saarland. The former Bond coach of the Dutch team, Max Merkel, nominated him for the match after a magnificent performance in the game of the Dutch B national team against Germany. This remained Baks single international match. His position in left midfield took over in January Klaassens.
Bak ended his athletic career at the age of 36 years. Then he worked until his retirement as head cashier at the Amro Bank.