The team from Solna fell off dramatically at the tail end of last season to miss out on Europe, but AIK have made a winning start under new boss Jose Riveiro.
Midway through the first half, a free-kick whipped into the box Aron Csongvai was headed against the post by Zadok Yohanna, and reacted quickest to the rebound Ibrahim Cisse, on hand to bundle it home.
1-0 was how things stayed until the 64th minute when Halmstad - tipped by many to have a tough campaign - levelled when a ball into the area was nodded down by Malte Persson into the path of Osto Liimatta, who lashed the ball into the net with the help of a big deflection.
But seven minutes from time, Riveiro and co. got their start they wanted when Yohanna cut inside from the right wing, fought his way past a couple of defenders and lashed the ball home from a tight angle to win it.
Following three goals in the Svenska Cupen group stage last month, it's a dream first Allsvenskan goal for the 18-year-old.
After a hugely disappointing 2025, Malmo showed little sign of improvement in the opening round under their new boss Miguel Angel Ramirez, needing to come from behind away at newly-promoted Orgryte, who were playing their first top-flight match since 2009.
The match was halted twice as supporters clashed with police at Gamla Ullevi, but the ugly scenes turned to joy for the home side six minutes into the second half, when a long throw into the box wasn't cleared by the MFF defence, and eventually Anton Andreasson pounced at the near post.
However, the record champions spared their blushes in the 73rd minute, but only with help from Orgryte goalkeeper Hampus Gustafsson, who spilled Noah Astrand John's shot at the feet of Erik Botheim, who tapped home the equaliser.
The top two in last year's Superettan probably weren't too thrilled about meeting again on their Allsvenskan return, but champions Vasteras are happier now after grinding out a narrow away victory.
The only goal came after 11 minutes, as the visitors attacked down the left and Marcus Baggeson's low centre was diverted towards his own goal by Achraf Dari, before Zakarias Ravik's failure to hook it off the line ensured it went down as his own goal.
Kalmar dominated the rest of the game with more possession and 16 shots to Vasteras' four, but with only three on target and no big chances, they will have to find their shooting boots soon if they are to stay up this season.
Vasteras had Jonathan Ring sent off for a second booking, but the red card came deep into added time and Kalmar didn't have enough time to profit from the extra man.