The 29-year-old enjoyed a standout 2017 after taking the captaincy reins from Nick Riewoldt at the end of 2016.
Geary finished third in the Trevor Barker Award, behind Seb Ross and Dylan Roberton, to reinforce his reputation as one of the best small defenders in the game.
Ross and Roberton, along with experienced midfielders Jack Steven and Jack Newnes, round out a five-man leadership group which was selected by the playing group as the men to lead the Saints in 2018.
Geary said he was honoured to be appointed skipper for a second year.
“It’s a huge honour to captain the club, and its humbling to be nominated by the playing group.”
“I really enjoyed taking on the role last year and gained a lot from the experience, which will hold me in good stead this season.
“Thankfully, I have a strong group of leaders supporting me and the playing group is as close as I have seen it in my time at the club.
“It’s a really exciting time for the Saints with the move to RSEA Park at Moorabbin getting closer, and we are leaving no stone unturned to make sure we take the next step on the field.”
Coach Alan Richardson said Geary had been super impressive since assuming the captaincy.
“I couldn’t have been more impressed with his leadership last season,” Richardson said.
“Jarryn is able to strike the right balance between supporting his teammates and showing great care, while also challenging those around him to improve.
“He’s been a leader at our club for many years, but to see him stamp his influence on this group has been great to witness.
“On game-day and on the training track, he sets incredibly high standards and that’s reflected in the consistency of his performances.”
Richardson said Geary was supported by a strong group of leaders who would help drive the standards needed across the playing group for the club take the next step this season.
“Dylan Roberton and Seb Ross were new to the leadership group last season and we saw in their performances how they coped with the added responsibility,” he said.
“Jack Steven, as a three-time best and fairest winner, is as influential as any player on our list, while Jack Newnes continues to be a model of consistency and someone who always puts the team first.
“This season we opted to reduce the leadership group from eight to five, which we felt would be more effective and the right number given how the group has evolved over the past four years.
“While this means that Josh Bruce, Dave Armitage and Mav Weller don’t have an official role this year, they remain important leaders within the playing group.”