The 27-year-old has been a free agent since his contract with Aston Villa expired, and the former West Ham midfielder wanted a move to Newcastle United.
Alan Pardew signed him for the Hammers when he was manager and turned him into star player, giving him the captain's armband.
It was thought the pair could be reunited at St James' Park, but (reading between the lines) Pardew seems to feel the outspoken midfielder could upset the apple-cart at St James' Park.
Having had Jose Enrique and Joey Barton hammer Mike Ashley in "tweets" recently, Reo-Coker could be one-too-many hot-heads at the club.
Reo-Coker has agreed a two-year contract with the Reebok Stadium club.
Croydon-born Reo-Coker, who joined Villa for £8.5million from West Ham in 2007, started his career with Wimbledon.
He was named captain by Gerard Houllier in the absence through injury of Stiliyan Petrov - and becomes Bolton's second signing of the summer, former Swansea midfielder Darren Pratley being the other.