The 2-1 home triumph earned Livi an unassailable 16-point lead at the summit with four games remaining.
After a flying Alloa start, the hosts' Josh Mullin and Jackson Longridge scored either side of half-time.
Dylan Mackin pulled one back for the Wasps, but Livi squeezed home, sealing their return to the Championship at the first time of asking.
Livingston needed only to avoid defeat to secure promotion, but when the visitors struck the post twice in the opening six minutes, a title-clinching result looked far from straightforward.
That was until Pittman produced a sweetly-struck 35-yard drive to nudge the home side ahead after 17 minutes - a lead they preserved until the interval.
David Hopkin's men upped the ante as the second half began, Longridge cutting in from the left flank and curling a right-foot shop beyond Neil Parry in the Alloa goal.
Livi's prolific Liam Buchanan was denied a 26th goal of the season when his penalty struck the post, and he illegally converted the rebound before any other player had touched the ball.
Mackin halved the deficit with 24 minutes to play, capitalising on confusion in the Livi box following a corner, and subjecting the home fans to a tense finale before the celebrations could begin.
Livingston manager David Hopkin: "I'm delighted for my team, my staff and everyone that's worked hard to get us back where we belong in the Championship.
"We went top in October and stayed there ever since. It's great credit to the players. Every one of them has been fantastic.
"It was important we bought right, and I made sure I did my homework to get people in. I knew Mikey Miller, Sean Crichton from my days at Morton, I knew they'd won the league, I knew Sean Burn had won the league.
"It was important I tried to get these guys in to try and mould a team and a squad together that had already seen this league through. It's a very difficult league, there are lot of good players and good managers in it. I'm delighted that we've kept going and got over the line."
Match ends, Livingston 2, Alloa Athletic 1.
Second Half ends, Livingston 2, Alloa Athletic 1.
Attempt missed. Jason Marr (Alloa Athletic) header from the centre of the box is close, but misses the top left corner.
Corner,  Alloa Athletic. Conceded by Alan Lithgow.
Corner,  Alloa Athletic. Conceded by Craig Halkett.
Attempt blocked. Calum Waters (Alloa Athletic) left footed shot from outside the box is blocked.
Foul by Alan Lithgow (Livingston).
Stefan McCluskey (Alloa Athletic) wins a free kick in the defensive half.
Substitution, Livingston. Nikolay Todorov replaces Daniel Mullen.
Corner,  Livingston. Conceded by Andy Graham.
Attempt saved. Nicky Cadden (Livingston) right footed shot from more than 35 yards is saved in the bottom left corner.
Foul by Stefan McCluskey (Alloa Athletic).
Scott Pittman (Livingston) wins a free kick in the defensive half.
Foul by Jason Marr (Alloa Athletic).
Daniel Mullen (Livingston) wins a free kick on the left wing.
Attempt missed. Calum Waters (Alloa Athletic) left footed shot from long range on the right is close, but misses to the right from a direct free kick.
Jamie Longworth (Alloa Athletic) wins a free kick in the defensive half.
Foul by Raffaele De Vita (Livingston).
Delay in match Shaun Byrne (Livingston) because of an injury.
Substitution, Livingston. Sean Crighton replaces Jackson Longridge because of an injury.
Substitution, Livingston. Nicky Cadden replaces Josh Mullin.
Substitution, Alloa Athletic. Jamie Longworth replaces Greig Spence.
Foul by Jon Robertson (Alloa Athletic).
Josh Mullin (Livingston) wins a free kick in the defensive half.
Substitution, Alloa Athletic. Stefan McCluskey replaces Kevin Cawley.
Goal!  Livingston 2, Alloa Athletic 1. Dylan Mackin (Alloa Athletic) header from very close range to the bottom left corner.
Corner,  Alloa Athletic. Conceded by Alan Lithgow.
Penalty missed! Still  Livingston 2, Alloa Athletic 0. Liam Buchanan (Livingston) hits the right post with a right footed shot.
Penalty conceded by Jason Marr (Alloa Athletic) after a foul in the penalty area.
Penalty Livingston. Josh Mullin draws a foul in the penalty area.
Greig Spence (Alloa Athletic) wins a free kick on the left wing.
Foul by Shaun Byrne (Livingston).
Jackson Longridge (Livingston) wins a free kick on the right wing.
Foul by Steven Hetherington (Alloa Athletic).
Corner,  Livingston. Conceded by Jason Marr.
Kevin Cawley (Alloa Athletic) wins a free kick on the left wing.
Foul by Jackson Longridge (Livingston).
Steven Hetherington (Alloa Athletic) is shown the yellow card for a bad foul.
Foul by Steven Hetherington (Alloa Athletic).
Josh Mullin (Livingston) wins a free kick on the right wing.
Livingston clinched the Scottish League One title with a victory over nearest rivals Alloa Athletic.