The Swedish football legend, who played for Celtic, Barcelona and Manchester United in an illustrious career, and his son Jordan, went to commiserate with the home supporters after two-late goals earned Halmstad a 2-1 win in a relegation play-off.
A section of the home support threw seats and flags at the Larssons and some masked supporters ran on to the pitch and demanded Jordan Larsson's shirt. As the young striker removed it, one of the fans appeared to strike him, which prompted an angry response from Henrik Larsson and his son.
Jordan Larsson had given Helsingborg the lead in the 83rd minute and had seemed to secure the club's top flight status only for Halmstad's two late goals in the 87th and 90th minutes.
Swedish football has been plagued by football violence for years. Only this season, a match between Östersund and Jönköpings Södra was abandoned when a fan ran onto the pitch and attacked the Östersund goalkeeper.
Earlier in the season, the top-flight game between IFK Göteborg and Malmö FF was abandoned after a supporter threw a firework at a Malmö player.
Swedish national football team captain, Andreas Granqvist, who started his career at Helsingborg, wrote an angry response to the hooligans on his Instagram account.
To all the idiots who call themselves HIF supporters and go onto the field, and attack their player and leader, never show yourselves at Olympia again !! HIF is bigger than you!"
Monday's sports pages were filled with unsubstantiated stories that an attack against Henrik Larsson had been pre-planned on social media.
Stefan Elofsson, editor at Swedish Radio's sports channel, Radiosporten, says that Helsingborg have not revealed too much about their security arrangements.
"How they evaluated it I don't really know, I think that they were living in denial about whether they would actually lose the game," he tells Radio Sweden.