Seth was born and raised in New England. He obtained a B.A. in Geology from Amherst College in 1997, moved to New Mexico the same year, and worked in the sciences prior to attending law school. In May 2007, Seth graduated from the University of New Mexico Law School, where he served on the UNM Law Review. After graduation, Seth clerked for the Hon. Lynn Pickard (Ret.) with the New Mexico Court of Appeals. He spent ten years in private practice, rising to shareholder at a major New Mexico law firm, before joining DACA in August 2019. Seth lives in Santa Fe with his wife Megan, their son Zeke, and a pug dog named Jake.