Hellendaal was born in Rotterdam on 1 April 1721, the son of Neeltje Lacroix and Johannes Hellendaal. Johannes earned a living to support his family as a candle-maker while seeking paid gigs, and teaching and working with amateur musicians. As a father, Johannes provided his son Pieter with an intense musical education, including organ and violin. In addition to his highly creative compositions and prodigious craft as a performer, Pieter in maturity maintained himself by compositions and self-publications that respected and supported amateur musicians.