Zach Harmon is an unlockable character in Guitar Hero: Metallica. He has been Metallica's guitar technician since the '80's. To unlock him you need to Get 100 stars in a band career mode.
Biography[]
"If someone was ever named president of Metallica, that would be crew guy Zach Harmon. For 20 years he has kept Metallica's gear going as the 'go-to guy' on the road and in the studio." — Zach Harmon's bio in Guitar Hero: Metallica.