Greg is a singer and evolutionary biologist. He is most recognized as the lead vocalist and only constant member of punk rock band Bad Religion, which he co-founded in 1980. He embarked on a solo career in 1997, when he released the album American Lesion. His follow-up album, Cold as the Clay, was released nine years later. His newest solo work is Millport, released in 2017. Greg obtained his PhD in zoology at Cornell University and has lectured courses in natural sciences at both the University of California, Los Angeles and at Cornell University.
Greg writes that he is an atheist: "I've never believed in God, which technically makes me an atheist". However, he prefers to identify as a naturalist rather than as an atheist, saying: "Evidence is my guide. I rely on observation, experimentation and verification."
He describes himself as Straight Edge which often includes a vegan philosophy but I'm not sure of his views on non-human sentient animal ethics.