Before the 2009 Christmas break, Casboult attended the team's controversial booze cruise (the fallout from which included the suspensions of Andrew Walker, Eddie Betts and Ryan Houlihan, plus a "please explain" to the club from the AFL); it was widely reported in the media that, in an initiation game, Casboult was handcuffed to an unnamed senior player and forced to match him drink-for-drink until barely conscious.

[7][8] Casboult won a regular place in the senior team in 2014, playing as a forward and sometimes as a back-up ruckman.

[10] Through the early part of his career, this strength in his game was offset by very poor goalkicking accuracy from set shots, returning less than 50% each season and not reliable even at close range;[11] but after working with former Collingwood and North Melbourne full forward Saverio Rocca in 2015 and again in 2017, became one of the team's most reliable set shots.

[12] He led the team in goalkicking for the only time in his career in 2017, with a return of 34 goals, 18 behinds, and signed a two-year contract extension with the club after the season.

[13] After a 2018 season was abbreviated by injury, Casboult returned as a regular to the team in 2019 and 2020, and began playing swing key position roles in both the forwardline and backline, as well as back-up ruck.