An early goal from the former Derby winger and one from the Greek striker either side of half-time give the Scottish champions the lead ahead of next week's second-leg in Glasgow
Neil Lennon's side must now finish the job off at Parkhead next Wednesday to qualify for the first time under the stewardship of the former Celtic skipper.
With less than two minutes gone in the game the visitors took the lead, as Samaras swung a cross from the left wing for Commons to volley past Par Hansson in the Helsingborgs goal to give The Bhoys the early advantage.
Celtic couldn't add to their advantage and spent the reminder of the half of the back foot, with Helsingborgs' new signing Nikola Djurdjic getting in behind Charlie Mulgrew, before taking aim at goal, but Fraser Forster got his body in the way to clear the ball.
On the quarter of an hour mark Thomas Rogne gifted possession to May Mahlangu with a poor clearance. The midfielder played in Alejandro Bedoya, but the former Rangers midfielder found Forster in superb form as he blocked the chance.
The home side continued to pile on the pressure, with Christoffer Andersson searching out Thomas Sorum inside the box, but his chipped strike from almost ten yards out was saved well by the Celtic stopper.
The Scottish champions were nearly the makers of their own downfall as a long ball from the Helsingborgs box following a Celtic corner was miskicked by Adam Matthews as he attempted to play the ball back to Forster, allowing Mahlangu a clear road towards goal, but the South African midfielder took too long and allowed Matthews to get back and clear.
Bedoya was next up to try his luck for the Swedish outfit as he got his head onto a cross from the left hand side by Andersson, but the American could only direct his effort wide of Forster's right hand post.
Lennon's side made to hold the floodgates for the reminder of the half as Djurdjic and Sorum continued to attack the Celtic box, but to no avail as the Parkhead side went to the dressing room with the crucial away goal.
The second half started in the same vein as the first, with Forster having to get down well in order to save a low strike from just outside the box by Mahlangu.
Andersson was next to have a strike at goal for the Swedish champions, after good work in the middle of the park saw the ball arrive at the feet of the 33-year-old, but his effort went wide of Forster’s right hand post.
Celtic finally started to get back into the game with some good work coming from substitute James Forrest, who started off a move which culminated with a strike from the Scotland international after some superb passing, but his effort went well wide.
Forrest was again at the centre of things minutes later as he made himself available for a short pass from a Commons corner on the left, and the winger proceeded to cross the ball into the danger area for Joe Ledley, but his header hit the top of the bar and went out of play.
Celtic were lucky not go down to ten men as Sorum got in behind Mulgrew to get onto a long ball and as he tried to play it past Rogne, the ball hit off of the defender's arm to give the Swedish side a free kick, but with the Helsingborgs side demanding a red card referee Olegario Manuel Benquerenca decided it only merited a yellow.
Helsingborgs then had a chance to get back on level terms as they worked the ball down the left wing, before finding substitute David Accam inside the box, but his effort went high and over the Celtic bar.
Forster was once again called into action for the Glasgow side as he grabbed onto a header from the right hand side of the box by Bedoya.
But Celtic claimed a crucial second goal with a quarter of an hour left, as Mulgrew swung a corner in from the right wing, with Samaras rising above the home defence to head home and put the Hoops in command in the tie.
The contest should have been over when Samaras got the ball in his own half and raced forward, with no defenders nearby, but once he got into the box, instead of squaring the ball to Commons, the Greek striker took on the shot and put it wide.
Lennon's side continued to pile on the pressure with Forrest racing down the right wing, but his shot went wide.
Then Mulgrew had a superb chance to put the game beyond doubt as Forrest crossed the ball in from the right, but the effort cannoned off the bar and went out of play.
But Celtic had to leave Sweden with a two goal lead as they look to continue their European adventure in the Champions League by finishing off the tie in Glasgow next week.