The balding 28-year-old defender has signed a four-year deal with the London club and is Gullit's second major capture since he took over from Glenn Hoddle last month.
Gullit, who recently persuaded his former Sampdoria colleague and Juventus striker Gianluca Vialli to join him at Chelsea, heard that he had won the race to sign Leboeuf when the club's managing director, Colin Hutchinson, and the coach, Graham Rix, were given permission to complete the deal at France's Euro 96 base in Wigan.
Gullit, meanwhile, learned yesterday that he will have to wait an extra 24 hours before beginning his managerial career in earnest. The dictates of Sky Sports' coverage of the Premiership means Chelsea's first match of the season, against Southampton at The Dell, will be before the satellite channel's cameras on Sunday 18 August.
Leeds United are hoping to sign Charlton Athletic's highly-rated Lee Bowyer. The 19-year-old midfielder has attracted the attention of several Premiership clubs, with Coventry and Sheffield Wednesday having offered around pounds 2.5m. Bowyer, however, appears to be heading to Elland Road after the player and his father met the Leeds manager, Howard Wilkinson, at the weekend.
"The move is now up to the boy," Wilkinson said. "He obviously wants to be sure that whatever move he makes is the right one and it's a case now of waiting for his decision."
Wilkinson sees Bowyer as a long-term replacement for Gary Speed, who moved to Everton last week in a pounds 3.5m deal.
Bolton have underlined their determination to regain a Premiership place at the first attempt by announcing a pounds 2.25m double-signing. The Danish midfield pair of Michael Johansen and Per Frandsen have agreed terms to move from FC Copenhagen.
Johansen, 23, is a Danish Under-21 player who captained the club last season. Frandsen, 25, has played in the full Danish international side and spent three seasons with the French club, Lille.
The deals represent Bolton's first move into the transfer market following their relegation to the First Division. They have money to spend following the pounds 3.5m sale of the defender Alan Stubbs to Celtic.
Birmingham City's pounds 1m bid for Blackburn's Mike Newell is being held up by the striker's wage demands.Reuse content