The visitors looked set to earn an unlikely point after Robbie Muirhead’s penalty had cancelled out a first-half opener from Marcelo Saracchi.
But with the clock into the second minute of time added on, Oxlade-Chamberlain curled an effort into the far corner to give his team the win that moves them to within six points of leaders Hearts, with a game in hand.
Celtic made six changes from the side that defeated Dundee in the Scottish Cup at the weekend.
In came Kasper Schmeichel, Saracchi, Benjamin Nygren, Sebastian Tounetki, Daizen Maeda and Arne Engels, replacing Viljami Sinisalo, Kieran Tierney, Hyunjun Yang, Reo Hatate, Joel Mvuka and Paulo Bernardo.
Livingston made five changes following their defeat to Falkirk in their last outing and handed starting berths to debutant Cammy Kerr, Danny Wilson, Emmanuel Danso, Scott Pittman and Stevie May.
Out went Connor McLennan, Babacar Fati, Mo Sylla, Joshua Brenet and Lewis Smith, while Samson Lawal was scratched from the line-up just before kick-off, with Ryan McGowan reinstalled.
Celtic started on the front foot and Callum McGregor saw a low shot pushed away by Jerome Prior before Tomas Cvancara should have done better than fire an effort into the goalkeeper’s arms.
Livingston responded with an early effort of their own as May fizzed in a shot that Schmeichel did well to keep out.
Most of the chances, though, were at the other end. Livi goalkeeper Prior did well to keep out Tounetki’s shot and then, barely a minute later, saved from Nygren, while Maeda -following up – could not steer the rebound past Kerr.
McGregor had another drive saved by Prior but, from the resulting corner, Celtic finally made the breakthrough after 15 minutes.
Engels’ corner was headed out to the edge of the box where Saracchi took one touch to control the ball before smashing his shot beyond the goalkeeper for his first Celtic goal.
The home side kept the pressure on and a neat and turn from Nygren was again well saved by Prior before Engels went off injured and was replaced by Hatate.
Liam Scales headed over with Celtic’ first chance of the second half before Livingston drew level.
Hatate brought down Muirhead in the box and the striker made no mistake with the awarded penalty.
Celtic pressed for a winning goal and it came deep into injury time as Oxlade-Chamberlain curled a shot from the edge of the box into the far corner to clinch maximum points.
St. Mirren’s Killian Phillips celebrates after scoring to make it 2-2 with Kilmarnock. (Photo by Rob Casey/SNS Group via Getty Images)
Rangers’ title hopes suffered a damaging blow as Stephen Welsh’s late leveller gave 10-man Motherwell a deserved 1-1 draw at Fir Park.
Midfielder Nico Raskin gave the visitors the lead with a well-worked goal after six minutes.
Lukas Fadinger was sent off for a 78th-minute foul on Mikey Moore, but 11 minutes later Welsh drove in a dramatic leveller to leave Rangers five points behind leaders Hearts.
Kilmarnock clawed themselves closer to safety thanks to a Tyreece John-Jules hat-trick in an enthralling 4-3 victory over St Mirren, for whom Ireland midfielder Killian Phillips bagged a losing brace.
The ex-England Under-21s forward added two second-half goals to a superb overhead kick as Killie edged a seven-goal thriller to move within three points of their opponents.
Aston Villa loanee Ben Broggio marked his full league debut with what proved to be Falkirk’s winning goal after Dundee’s Yan Dhanda missed a stoppage-time penalty in their 1-0 defeat.