The 40-year-old former Scotland international received the accolade to acknowledge a 21-year career, during which he has chalked up more than 1,000 senior appearances.
Previous winners of the PFA Merit award include Sir Alex Ferguson, Sir Bobby Robson and North End legend Sir Tom Finney.
Having started his career at Scunthorpe, Alexander initially moved to Preston from Luton in March 1999 and returned to Deepdale in the summer following a four-year spell with Lancashire neighbours Burnley, during which he burst through the 1000-game barrier when he featured as a substitute in a 2-1 home win over Swansea last April.
He started 17 games for the Lilywhites this term before being sidelined by a hamstring injury, and is currently undertaking a coaching role having served as interim manager alongside David Unsworth before Graham Westley's appointment as Phil Brown's successor.
"To get recognition for what you have done in your career at any stage is great," Alexander said. "I'm coming towards the end of my playing career and I'm privileged to be recognised by the people who I have played against for the last 20-odd years."