The 42-year-old is the first Welshman to be awarded the prize and follows in the footsteps of fellow Manchester United United greats Sir Alex Ferguson, Sir Matt Busby and Sir Bobby Charlton.
Giggs made a club record 963 United appearances and is the most decorated player in English football.
"I'm fortunate to win it and I'll enjoy it," he said.
"When you win each award you look down the trophy and you see the players who have won it before and you realise what a great accolade it is.
"This is the same. I've been here on the nights when people have won it and it's legends of the game."
Now assistant to manager Louis van Gaal at Old Trafford, Giggs won 13 league titles, four FA Cups and two Champions League crowns during a glittering career.
The accolade completes a hat-trick of major PFA awards for Giggs who was Player of the Year in 2009 and Young Player of the Year in 1992 and 1993.
Giggs said: "I'm chuffed to have to have won all three awards; the young player was a long time ago and then the player award was a big surprise.
"This is the culmination of around 25 years since my debut."
Watch highlights of the PFA awards on BBC One on Monday. The programme starts at 23:30 BST (Northern Ireland 23:45 BST and Wales 00:30 BST on 26 April).
Ryan Giggs says he is "fortunate" after winning the Professional Footballers' Association merit award.