Vonk was born in Uitgeest and came out all his player career in Noord-Holland. He played 306 matches for AZ’67 between 1968 and 1978 and managed to score 11 goals. Vonk also played a season for FC Volendam, in which he scored six times.
After his career, Vonk remained active in professional football. In 1979 he became an assistant trainer at AZ’67, with which Vonk celebrated the national championship in 1981.
Trainer jobs at FC Twente, the Spanish Real Burgos and FC Groningen followed before returning to AZ. Between 1995 and 1997, Vonk was head coach in Alkmaar.
Theo Vonk was the father of Michel Vonk, who played for AZ and Manchester City and was a trainer of Telstar and AZ.