Boak's elevation to the captaincy means veteran Dom Cassisi has been relegated after four years in the role.
Boak, 24, served as vice-captain under Cassisi last year after being named in the Power leadership group in 2011.
The talented on-baller signed a new contract with Port at the end of the 2012 campaign, to quash speculation that he could head back to his home state of Victoria.
He becomes the 69th captain in Port Adelaide's history and the fifth at AFL level.
Boak said he was thrilled by the appointment.
“It’s a great honour to be captain of this great club and have the opportunity to play a role that so many outstanding players have filled in the past,” Boak said.
“To take over from Dom who has done such a fantastic job for the club and our group of players is a real privilege for both Brad and me."
Boak said despite Cassisi's relegation from the captaincy, he would still continue to look to the veteran for guidance.
“Dom is a true leader of this club and we’ll always work with him to make sure we keep building on the change we’ve had in the pre-season and continue working hard and doing everything we can to make the club really strong,” Boak said.
Ebert, 22, played his first season with Port Adelaide last year after requesting to be traded back to his home state, following a four-year stint at West Coast.
Ebert said he would relish the opportunity to be a part of the leadership for the club he grew up supporting.
“It’s a huge honour having grown up supporting this footy club and watching some of the past players and leaders, so it’s great to have a role supporting Boaky and everyone else involved," Ebert said.
“Going forward, we know that there is plenty of room for improvement on last year and a lot has been done over the pre-season to make sure that we rectify that and improve on where we were.
“I’m excited about going forward and I know Travis is and the rest of the boys are.
“Having this responsibility now is largely about making sure the improvement starts happening on the field, but so far we feel really good about what we’ve done.”
New Port Adelaide coach Ken Hinkley said the time had been perfect for Boak and Ebert to step up.
“Coming in as a new coach, I had the benefit of being able to really take a fresh look at all the players’ leadership qualities over the past three months,” Hinkley said.
“We’ve watched the actions of the boys throughout pre-season right back to the trip overseas in late October, looking at their ability to show leadership and demonstrate it on a daily basis.
“There’s no doubt that we have got the right leaders in Travis and Brad. They are players of significance ready to play important roles on the field and off."