Several clubs had sounded out Boak and it is a significant coup for the Blues, who have revamped their football department in the wake of their disappointing season.
Coach Michael Voss and new football manager Chris Davies worked with Boak at Port Adelaide.
Boak, 37, retired at the end of the season on 387 games - the Port club record.
He was their captain for six seasons, made three All-Australian teams and won two club best-and-fairest awards.
But the numbers do not properly reflect the lofty standing Boak has in the game for his character.
He famously rejected a recruiting bid from Geelong, who tried to lure him out of Port Adelaide back to his home region.
Boak will work at Carlton three days a week.
"Having worked with Travis for over a decade, I've seen first-hand his professionalism, leadership capabilities and commitment to helping those around him grow both as people and athletes," Davies said in a club statement.
"Travis will be an invaluable sounding board for our leaders and broader playing group, driving a renewed focus on culture and standards within our department as a whole."
Boak said the Carlton job was "a clear standout" among the post-football opportunities put to him.
"I am passionate about leadership and helping players not only grow in this space but thrive, while getting the absolute best of themselves in high-pressure environments," he said.
"I can't wait to get to work with this group.
"It is really clear to me that this club has a clear direction, a strong vision and most importantly total alignment on what that looks like across the board, which was a massive reason why I wanted to be part of what is building here at the Blues."
Boak will also play for his junior club Torquay in the Bellarine League next year, and will wear the No.5 guernsey.
His father Roger, a Torquay club great who died of cancer when Boak was a teenager, had the same number.
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