Amon told the Power earlier this week he would be leaving, with Hawthorn, Melbourne and St Kilda among the clubs keen to secure his services.
The Hawks announced on Friday that Amon had chosen them as his destination of choice, with the 27-year-old expected to sign a four-year deal once the free agency period begins on September 30.
Hawthorn have missed finals for four straight seasons and Amon’s arrival will help bolster a developing squad.
“It’s certainly great news for the club to hear that Karl wants to be a part of what we are building here at Hawthorn,” Hawthorn’s list manager Mark McKenzie said in a statement.
“Karl complements our current list strategy and the direction we are taking as a club.”
Amon has played 124 games since being snared by Port Adelaide with pick No.68 in the 2013 national draft.
His best game this year ironically was against Hawthorn, when he tallied 38 disposals and five clearances in round two.
Amon’s exit follows Port Adelaide’s delisting of Sam Skinner, Sam Mayes and Taj Schofield.
Veterans Robbie Gray and Steven Motlop have retired.
-AAP