The Western Hockey League club announced on its website Wednesday that the 60-year-old from Oak Bank, Man., would also have the title of senior vice-president of hockey operations.
Paddock coached the Ottawa Senators for a season in 2007-08 as well as the Winnipeg Jets from 1991 to 1995. He spent the last five seasons with the Philadelphia Flyers as an assistant coach and assistant general manager.
Chad Lang will continue in his job as the Pats general manager and senior vice-president of hockey and business, the team said in its statement.
Paddock replaces Malcolm Cameron, who was fired in June after leading the Pats to a 39-26-4-3 record and a divisional title in 2013-14.
The Pats ownership changed hands this spring when Russ Parker sold the team to Queen City Sports and Entertainment, headed by president Anthony Marquart.
"We went through an exhaustive search to find the right fit for our hockey club and in John we found exactly what we need,” Marquart said in the statement.
"His extensive hockey experience in coaching and management is an asset as we work to build a solid foundation and develop our hockey club for future success."
Winnipeg's record in Paddock's four seasons behind the bench was 106-138-37. The Jets made the playoffs two of those years and lost in the first round both times. The Senators went 36-22-6 and did not make the post-season his one season there.
Paddock is a member of the American Hockey League's Hall of Fame and has the third-most coaching wins in league history with a record of 589-438-98.
He's the only coach to win a Calder Cup with three different teams, which he did in 1984 with Maine, 1988 in Hershey and in 2000 with Hartford.
Paddock played junior hockey for the WHL's Brandon Wheat Kings and was a third-round draft pick of the Washington Capitals in 1974. He played 84 career NHL games with Washington, Philadelphia and the Quebec Nordiques.
The Pats have scheduled a news conference with Paddock for Aug. 21, when the Pats open training camp.