Proctor has moved to the Liberty Stadium for an undisclosed fee and will initially join the club's Under-21 setup.
He will feature for the Swans in the the Under-21 Premier League and chairman Huw Jenkins believes that the newly-formed structure will help nurture promising talents into future first-team players.
Jenkins said: "The Under-21 structure will replace the old reserve team set-up. We see it as an important and vital part of the club's long-term future.
"Our aim is to establish a promising group of youngsters under the Under-21 banner who can develop and progress into Michael Laudrup's first-team plans."
Proctor scored three goals in 31 appearances for Preston last season, but was largely used as a substitute.