Ajax headed into the match top of the table and needed just a point at De Vijverberg to wrap up the title, but goals from Lasse Schone, Nicolas Tagliafico and a double from Dusan Tadic saw them take all three and finish the season three points clear of PSV.
The game exploded into life just before half-time with three goals scored in seven minutes. Set-piece expert Schone put Ajax ahead with a well-taken free-kick before midfielder Youssef El Jebli levelled for De Graafschap three minutes later. But Tagliafico had the visitors back in front on the stroke of half-time.
Ajax extend coach Ten Hag's contract till June 2022
Ajax ensured the points and the title in the second half when Tadic first scored from the penalty spot before the club's top scorer grabbed his 28th league goal of the season late on.
Erik ten Hag’s side win the title for the first time since the 2013-14 season and complete their first domestic double in 17 years.
Ajax ended with 86 points and 119 goals scored in 34 games. PSV collected 83 points to join them in next season's Champions League.
Feyenoord came third after winning 4-1 at Fortuna Sittard, the last game in charge for their coach Giovanni van Bronckhorst.
The win will go some way to helping Ajax fans forget about their Champions League heartbreak, when Tottenham scored three second-half goals in last week's semi-final second-leg to progress to the final on away goals.
Ten-man Ajax close gap on PSV to just two points
Stam to be next Feyenoord coach