Josh Hennessy was born February 7th, 1985 in Brockton, Massachusetts. San Jose's second-round, 43rd overall selection in the 2003 NHL Entry Draft, Hennessy is a graduate of the QMJHL's Quebec Remparts.
An excellent playmaker, Hennessey made his QMJHL debut in 2001-02 with the Ramparts and finished atop his club in points by a rookie. Over the next two seasons he continued to contribute offensively with the Remparts, tallying 166 points. After representing the Remparts as an assistant captain in 2002-03, Hennessey was named the club's captain at the start of the 2003-04 season. In his final junior season, Hennesy again represented his club as captain and led the club in scoring with 85 points in 68 games.
Following his remarkable junior career, Hennessy appeared in his first professional season in 2005-06 with the Sharks' AHL affiliate in Cleveland. That season he led the club in goals, assists and points in 80 games and was named his teams Rookie of the Year. Despite a productive first professional season, the San Jose Sharks dealt him to the Ottawa Senators, via the Chicago Blackhawks in a three-way deal in the summer of 2006.