Sveinn Aron spent the first three years of his senior club career in Icelandic leagues, first 1. deild karla and then the top-level Úrvalsdeild karla.
On 26 July 2018, he signed with the Italian Serie B club Spezia.[1] He made his Serie B debut for Spezia on 29 September 2018 in a game against Carpi as a 59th-minute substitute for Andrey Galabinov.[2]
On 29 August 2024, Sveinn Aron signed a contract until 2028 with Sarpsborg in Norway.[8]
International career
Sveinn Aron represented Iceland at the 2021 UEFA European Under-21 Championship, where he started in the first two group stage games, both of which Iceland lost (he scored the squad's only goal at the tournament in a 4–1 loss to Russia). Instead of playing in the closing game on 31 March, he was called up to the senior squad and made his debut for it on the same day in a World Cup qualifier against Liechtenstein.[9]