Jack, the son of former Rugby start Garry Jack, will join Jarrad McVeigh as co-captain of the Swans in 2013.
In what came as a surprise decision to many, Goodes said the timing was right to step down.
“I just think the feeling is right,” Goodes told sydneyswans.com.au on Friday.
“Going to Coffs Harbour and doing the behaviours again, and with the guys who were stepping up in those meetings, it just felt like it was a good opportunity to give someone else an opportunity to have this great opportunity that I’ve had.
“I’m grateful to still be playing football for this great club after a premiership year and I just think the time is right and I’m looking forward to helping mentor the next person who goes into that role just as Kirky and Craig Bolton did for me and I did for Macca (Jarrad McVeigh) over the last couple of years.”
Despite removing himself from captaincy Goodes said he will remain in the leadership group at the Swans.
“I’m not going to step back out of the leadership group and I want to be a part of it and I still want to drive our team forward, but I think it’s a great opportunity for someone else to come forward and to take up that co-captain role,” he said.
Jack, 25, began his AFL career in 2005 when the was drafted on to the Swans rookie list. Since fighting his way on to the senior list in 2007 the hard runner has played in 114 senior games for the Swans and played a pivotal part in their 2012 Premiership kicking 2 goals.
“I’m obviously really honoured and humbled to receive this opportunity to co-captain with Jarrad,” Jack said at Fridays press conference.
“It’s a club that I’ve followed since I was a kid and they gave me an opportunity when a lot of clubs said I wasn’t good enough.”