Widmayer played in the inaugural World Matchplay in 1994, losing 6–8 in the first round to Keith Deller.

Prior to the 2011 Winmau World Masters, Widmayer damaged his arm whilst clearing fallen trees in the wake of Hurricane Irene.

Widmayer qualified for the 2014 World Championship and entered in the preliminary stage, where he upset Garry Thompson 3–2 in sets.

In the 2015 World Championship, Widmayer again entered in the preliminary stage, where he fought back to beat Rhys Hayden 3–2 in sets after being 2–0 down.

He gained his revenge with a 3–1 victory, setting himself up with a tie against Martin Adams in the second round, which he lost 4–0.