The Saints will send pick 10, a 2020 second-round selection and pick 58 to the Dockers, as well as midfielder Blake Acres.
St Kilda has also added a future fourth-round pick to the deal, with the Dockers sending a third-round pick from 2020 along with Hill.
Acres had a medical at Fremantle on Tuesday, and has now been included in the Hill deal.
“To secure a player of Bradley’s calibre is extremely exciting for the club and our supporters,” St Kilda’s List Manager James Gallagher told saints.com.au.
“He wins a lot of the ball, uses it well and has performed at a very high level over a long period of time, and pleasingly believes his best football is ahead of him.
“We started the Trade Period knowing it would take a significant deal to satisfy the Dockers.
“Thankfully, we have been able to reach an agreement which reflects Bradley’s value as a contracted player and one of the game’s best outside midfielders.”