The announcement came just hours after the Barclays Premier League club revealed United States captain Clint Dempsey was returning on a two-month loan from Seattle Sounders.
It has been a time of change recently at Craven Cottage with former manager Martin Jol sacked on December 1 to be immediately replaced by Rene Meulensteen.
Tuesday's arrivals of Curbishley and Dempsey will give the fans hope the club can start to improve on the field as they sit second from bottom at Christmas.
While Dempsey returns from Seattle Sounders in the Major League Soccer off-season, for Curbishley it is his first role at a club since leaving the Hammers in September 2008, despite being linked with many managerial vacancies.
A statement on Fulham's official website read: "With a wealth of football experience behind him, Alan will work with head coach Rene Meulensteen as the club embarks on the second half of the season, and the important task of securing our Barclays Premier League status for a 14th consecutive campaign.
"Both Curbishley and Meulensteen will report to the club's CEO Alistair Mackintosh."
Meulensteen said: "I'm very happy that Alan has joined us as I know his expertise will be invaluable as we enter the remaining months of the season.
"Following Martin [Jol's] departure I discussed with both Alistair Mackintosh and the chairman the challenges we face, and I was delighted that they supported the idea of additional support within the coaching team.
"Alan has a proven track record in the industry and understands full well what it takes to succeed.
"I look forward to sharing ideas and listening to advice, to ensure Fulham Football Club remains where it belongs: in the Premier League."