After another excellent season in 2007, Cassisi accepted a three-year deal with the club, ensuring that he would stay with Port until 2010.

In 2008 he undoubtedly played his best season, averaging 22.7 possessions and 6.3 tackles per game[1] and finishing second in the club best and fairest (career best).

[2] In 2009, Cassisi was named captain of the club succeeding Warren Tredrea and replacing the #25 guernsey he had worn since debut.

Before the 2013 season, Cassisi handed the captaincy to Travis Boak and returned to the number #25 guernsey.

[3] Cassisi officially retired from the AFL on 17 July 2014 and played his final game in a three-point win against Melbourne in round 18.