Pruitt, who helped coach the Seminoles to the BCS national title in his first season as defensive coordinator at the school, replaces former Georgia DC Todd Grantham, who resigned Sunday to accept the same position at Louisville.
Georgia coach Mark Richt said Tuesday he is "ecstatic" to hire Pruitt, who has coached on three straight national championship teams at Alabama and Florida State.
Pruitt will earn $850,000 annually at Georgia, according to people familiar with the search. Pruitt made $500,000 at Florida State this past season but was expected to receive a significant raise after helping the Seminoles finish 14-0.
Under Pruitt's direction, Florida State finished No. 1 among FBS teams in scoring defense (12.1 points a game) and No. 3 in total defense (281.4 yards a game).
Pruitt also was Florida State's defensive backs coach, and the Seminoles ranked second in the nation in passing efficiency defense.
Pruitt, who was in Athens on Tuesday, said the move to Georgia "is an outstanding professional and personal opportunity."
"I'm looking forward to meeting the current players and getting on the road to visit with recruits," Pruitt said.
Georgia expects to return 10 starters on defense.
Pruitt already has a close relationship with at least one Georgia assistant coach. Pruitt began his playing career at Middle Tennessee State before transferring to Alabama, where he was roommates with Georgia offensive line coach Will Friend.
Before moving to Florida State, Pruitt was the secondary coach at Alabama for three seasons, including the Crimson Tide's national championship teams in 2011 and '12.
With the Feb. 5 national signing day only three weeks away, Richt moved quickly to hire Pruitt, who is known as a strong recruiter.
Pruitt produced instant results in his one season at Florida State.
"He taught us the ins and outs of everything," Florida State safety Terrence Brooks said recently. "Just the way to pursue to the ball, the way to go get the ball, everything you can think about in football he's taught us. He really broke the game down to us as to why we're running this type of defense.
"He makes you understand it so much better and I feel like everyone bought into it and that's why we're so successful."
Grantham was named Louisville's defensive coordinator on Sunday. He was the second defensive assistant to leave Georgia. Secondary coach Scott Lakatos resigned on Thursday, citing undisclosed personal reasons.
Under Grantham, Georgia's defense produced mixed results.
In 2011, the Bulldogs ranked fifth in the nation in total defense. His 2012 defense was packed with talented players, sending seven players to the 2013 NFL draft, but was perceived as underachieving.
Grantham had to rebuild the defense in 2013, when Georgia ranked only eighth in the Southeastern Conference in total defense and 78th in the nation in scoring defense. Georgia gave up 29 points per game to rank 78th in the nation as the Bulldogs finished 8-5.
Georgia did not announce if Pruitt will coach defensive backs at Georgia. Pruitt is scheduled to meet with reporters in Athens on Wednesday.
The signature play of the 2013 season for Georgia's defense came in the Bulldogs' 43-38 loss to Auburn. Nick Marshall's 73-yard pass was deflected by Georgia defensive back Josh Harvey-Clemons and then caught by Ricardo Louis for the go-ahead touchdown with 25 seconds remaining.
The Associated Press contributed to this report.