Forte struck from inside the penalty on 59 minutes to win the game for Latics against already-relegated Crewe to seal the club’s League One status for next season.
Manager John Sheridan opted to stick with the same side which beat Southend United in midweek with George Edmundson retaining his place at the heart of the defence.
It would be the visitors which started the game the better of the two teams, with striker Marcus Haber heading inches wide of Joel Coleman’s goal.
Coleman would be the busier of the two goalkeepers in the opening 45 minutes and he was called into action to deny the same player from close range.
Latics were sluggish in possession and struggled to get hold of proceedings as the half went on.
Tim Dieng shaped one from the edge of the box which the goalkeeper saved, whilst Curtis Main volleyed over from just inside the six-yard box.
Haber was proving to be a threat in front of goal and Coleman tipped over his headed effort midway through the half.
Lee Croft tried an ambitious effort on the half hour mark which was blocked whilst Tareiq Holmes-Dennis volleyed over from 25 yards as Latics struggled to find a way past the resolute Crewe defence.
Crewe’s George Ray was booked with five minutes of the half remaining, whilst the Railwaymen should have opened the scoring minutes later.
Callum Saunders broke the offside trap but Coleman again came out on top as he parried his shot wide.
Latics ended the half stronger with Liam Kelly driving a shot inches past the post and Main forced a strong save from Ben Garratt as he palmed his volley wide from six yards.
Athletic knew they needed to be better in the second half but again started lacklustre with Crewe looking to likelier of the sides to get the opening goal.
Brian Wilson was forced into some last ditch defending, clearing underneath his own crossbar from a Haber header whilst minutes later, Jamie Jones hit the side netting from a tight angle.
Against the run of play, Latics did take the lead on the hour mark through Forte.
Dieng ran on to a loose pass, crossed into the box and Forte wrapped his foot around the ball to guide in off the post past the goalkeeper.
Latics quickly went in search of another goal as Holmes-Dennis crossed for Main but his effort went over the crossbar.
Croft was forced off with injury 20 minutes from time, being replaced by Carl Winchester.
It was the hosts who were putting the pressure on the home side with waves and waves of attacks.
Substitute Brad Inman forced an excellent save from Coleman as he clawed the ball wide after it looked in all the way.
It would be Inman again who had the chance to equalise but his shot from just inside the penalty area went wide of the goal.
Latics ended the game strongly with substitute Dominic Poleon forcing a good save from Garratt, and Dieng’s shot was blocked from 18 yards.
That was the final chance of the game as the win secured Oldham Athletic’s Sky Bet League One safety with two games remaining.
Oldham Athletic: Coleman, Dummigan, Edmundson, Gerrard, Wilson, Holmes-Dennis, Dieng, Kelly, Croft (Winchester 69’), Forte (Poleon 77’), Main.
Subs not used: Cornell, Mills, Brown, Cassidy.
Crewe Alexandra: Garrett, Turton, Guthrie, Ray, Haber, Saunders (Inman 69’) Fox, Bingham (Ainley 79’), Jones, Kirk, Bakayogo.
Subs not used: Richards, Davis, Nugent, Cooper, Udoh.
Goals: Oldham Athletic (Forte 59’) 1-0 Crewe Alexandra
Attendance: 4,571 (98 visiting supporters)