Crawley announce Gregory as new manager
The League One club, currently 15th, announced Gregory's appointment on Tuesday and the former Aston Villa, Derby County and QPR boss has agreed an 18-month deal.
Barker left his post last Wednesday following 15 months in charge, with Gregory tasked in the short term with halting an eight-game winless league streak.
It is a challenge the 59-year-old is relishing, having been out of work since departing Kazakhstani side Kairat in 2011.
"I'm delighted to be here, back in English football at a club who have made tremendous progress over the last three years," Gregory told the club's official website after ending his six-year exile from the English game.
"When I met the directors I was impressed by their ambition to keep on moving Crawley Town forward.
"You can't stand still in football and the potential at this club is enormous.
"We have got a good squad of players and I have every confidence that they can challenge for the play-offs.
"You have to aim high and I'm really looking forward to getting on the training ground with the players and kicking on."