The 34-year-old former Ivory Coast international has joined the Scottish Premiership club for the remainder of the 2015/16 season.
Deemed arrives at Tannadice following his release by West Ham United at the culmination of last campaign and admits he is excited to play a key part for Terrors boss Mixu Paatelainen.
"Once I spoke to the head coach, I was excited by the challenge of Dundee United and the role he has planned for me. I want to identify myself with the club," said Demel on the club's official website.
"I have many years of experience in football and if I can use my knowledge to help the younger players here, that is what I will do.
"I have been training hard and I can't wait to play for Dundee United. I am ready as soon as the head coach needs me."
Guy Demel joins the Tangerines. #WeAreUnitedhttps://t.co/iek1Ywhdsvpic.twitter.com/b2seYKlm4F
— Dundee United FC (@dundeeunitedfc) November 23, 2015