At 14, Dave Vose became Erna's new instructor. He signed his first record deal in 1993 with a band called Strip Mind. Their debut album What's in Your Mouth sold fewer than 50,000 units. Some of the band members (mainly the singer) and Erna didn't get along, and Erna was booted out. They split-up shortly after.
In Godsmack concerts, Erna plays the bongos and a large drum set, staging a drumming duel known as "Batalla de los Tambores" with drummer Shannon Larkin. This battle has become a staple of the band's live show. He is also a harmonica player as present on the Godsmack song "Shine Down".
In 2010, Erna released his first solo album Avalon. The album took seven years to complete and differed stylistically from Godsmack. Erna wrapped up his acoustic tour with one final show at The House of Blues in Las Vegas, Nevada on June 28.
Erna has also worked with his local music scene. In April 2005, he participated in New Hampshire's Battle of the Bands Competition. The winner (a band called Zion who hails from Salem) had the opportunity to record a demo at Erna's California studio.