He is the brother of Ed Kowalczyk, lead singer of the band Live.

Kowalczyk was born in York, Pennsylvania to a family of Polish descent.

While studying in the Radio, Television and Film program at Philadelphia's Temple University, he started writing songs and performing with his first band, Portion.

In 1999, Adam began playing as the touring rhythm guitarist[2] for Live, a position which he held for 10 years.

During his time with Live, Kowalczyk relocated to Los Angeles and formed the band Adam & the Weight, which released the album Looking Up from the Ground in 2003.