Harshal Patel's coach Tarak Trivedi was instrumental in him becoming a cricketer. During his early days, when Patel's family was keen to move to USA, his coach convinced the family to stay in India for Patel to pursue his cricket career. Hailing from Gujarat, Patel was impressive at the Under-19 level but the state selectors ignored him for the first-class side.
However, Patel moved to Haryana, where he was under the watchful eyes of former England cricketer Ian Pont, who helped him develop his skills. Eventually, he made his first-class debut for Haryana against Delhi in 2011 and ended the season with 28 wickets from 7 games. Having been picked up by Mumbai Indians in 2010, Harshal was picked up RCB for the 2012 season of IPL. He stayed with RCB till 2017 before moving to Delhi Daredevils for the 2018 edition.
