Cassisi was chosen for the position despite coach Mark Williams initially nominating now Hawk Shaun Burgoyne as his preferred captain after former skipper Warren Tredrea stepped down from the role.
"When 'Choco' [Williams] told me about the captaincy, internally between me and 'Choco' it was fine and I understand why he said what he did, because Shaun and Chad [Cornes] were our vice-captains at the time, when 'Tredders' relinquished the captaincy," Cassisi told afl.com.au.
"Anyone would've thought they were the next two guys to take the rein, but I went through the process and I was fortunate enough to get the job, so it was as black and white as that.
"'Choco' was supportive of me right from the start, so we've moved on from there and we're working well together and looking forward to getting a good result."
Cassisi said after a natural learning curve, he is more confident entering 2010.
"After the first four or five rounds [last year], I was able to find a better balance between the captaincy stuff and being able to perform still," he said.
"I got off to a slow start, but sitting down with 'Choco' and getting back to the basics, I was able to get some momentum from there. Last year was a challenging year, but I'm more equipped for this year."
With Burgoyne now gone along with fellow premiership players Peter Burgoyne, Brendon Lade and Toby Thurstans, Cassisi said the club was looking to the new wave.
"The group is moving forward and it takes time to get experience into the new guys, but it's really exciting and they bought a lot of enthusiasm and competition to our training, which has been really good," he said.
Another 2004 premiership player, Kane Cornes, is not in this year's leadership group, but Cassisi said that wouldn't stop the gun ball-winner playing his part at the club.
"Kane has been fine with it. Kane and I came into the system 10 years ago and we understand that clubs evolve and leadership groups evolve and he enjoyed his three or four years in the leadership group," Cassisi said.
"He was vice-captain and he loved every minute of it, [but] the club's evolving and some younger guys have got an opportunity now. He's still got a really important role at our club with our leadership, and Chad's no different as well.
"He's handling it well and he's looking forward to a really good year."
With Lade now a Richmond assistant coach, Dean Brogan will be carrying much of the Port Adelaide ruck load. But the likes of Matt Lobbe and Jarrad Redden will also be jostling for a position, with Justin Westhoff also likely to spend time in the ruck.
Although ex-Pie and Blue Cameron Cloke was not named as a nominated rookie on Tuesday - Cameron Hitchcock was instead - Cassisi said the decision highlighted the small forward's form and was no comment on Cloke.
"It's just a reflection that we've still got a few options," he said.
"'Clokey' when he did get his opportunity did really well as well, so all of a sudden we've got a fair few guys to back up 'Brogs'.
"Who the club goes with next week, time will tell, but we're pretty confident we have some rucks backing them up."
As for expectations in 2010, Cassisi said a return to the top eight was on the agenda.
"We just missed out on finals last year, but the season probably felt a little bit worse and we only just missed out, so to improve on last year and play in the finals - that's what we aim to do every year," he said.
