Erlandsson was born in Malmö, Sweden to a Swedish father with Romanian roots. He's the older brother of Daniel Erlandsson, the drummer of Arch Enemy, and ex-Carcass. They both grew up together in Sweden and started playing drums at a very young age but with Adrian's career beginning in 1981 at the age of 11 after getting his first drum kit, and started to play with friends began playing covers of classic rock songs. He got his brother into drumming as Daniel admits "If it wasn't for him I probably wouldn't be playing today." They also started playing with their music teacher at school, and eventually began to write their own songs and formed a band.