Penrith were admitted to the New South Wales Rugby League (NSWRL) competition in 1967. Penrith struggled for almost twenty years before finally reaching their first finals series. The club achieved its first Grand Final appearance in 1990 but were beaten by the Canberra Raiders 18–14. The following year the Panthers met the Raiders again in the 1991 Grand Final, this time winning the game 19–12.
Penrith's most recent premiership achievement was over the Sydney Roosters in the 2003 Grand Final where Penrith were considered underdogs but came out on top with an 18–6 victory. In 2020 the Panthers reached their fourth grand final but were beaten 26-20 by the Melbourne Storm.
Ivan Cleary was appointed head coach in October 2018. OAK Milk has been their major sponsor since 2012.