The 20-year-old has signed a two-year contract at the Liberty Stadium and becomes the sixth signing of Michael Laudrup's time in charge following the acquisitions of Michu, Chico Flores, Jonathan de Guzman, Itay Shechter and Kyle Bartley.
Swansea are awaiting international clearance for the move, and Proctor will initially join the club's Under-21 set-up, and is set to feature in their season-opener on Monday.
He told the club website: "I'm delighted to join Swansea.
"The club has enjoyed a lot of success over the last few years and their style of football has really caught the eye."
He added: "I'm looking forward to being a part of things and trying to impress the new manager enough to force my way into his plans."
Proctor worked his way through the ranks at hometown club Preston, with his impressive academy displays earning him a first professional contract in January 2010.
He suffered a double hernia last season but was still able to make 31 League One appearance for North End, scoring three goals.
With Proctor starting his career in the new Under-21 league, which replaces the old reserve set-up, chairman Huw Jenkins is hopeful the emphasis on developing young talent will reap dividends for Swansea and the player.
He said: "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.
"It's important to think about the present, but it's even more important to think about the future."
Swansea are also closing in on a seventh summer signing with Valencia's Pablo Hernandez thought to be nearing a move to the Liberty Stadium for a fee of around ?4million.
Bringing in the Spain international, with Scott Sinclair set to head through the exit door, would be a major coup for the south Wales club.