He is known for playing Gary Mallett in the ITV soap opera Coronation Street from 1995 to 2000, having previously appeared in 1987 as Pete Jackson.
On leaving school, Mercer trained as an electrical engineer but decided to become an actor when he became an assistant stage manager at the Oldham Coliseum in 1979.
His first television appearance was as Mile in Starting Out (1982), a series made by ATV for schools and written by Grazyna Monvid.
[1] His television and film acting credits include leading roles as a butcher in Blue Money (1985), Coronation Street (as Gary Mallett and in 1987, Pete Jackson), Shackleton (with Kenneth Branagh), Heartbeat, The Monocled Mutineer, A Touch of Frost, Cracker, Common As Muck, Peak Practice, New Tricks and Master and Commander: The Far Side of the World (with Russell Crowe).
During August and September 2015 he returned to Doctors playing the recurring role of Andy Weston in an ongoing sub-plot.