An Oregon native, she earned her Ph.D. in religious studies at the University of North Carolina at Chapel Hill, where she specialized in the religious history of the American West. Her first book, Constructing Lives at Mission San Francisco: Native Californians and Hispanic Colonists, 1776-1821, examined the ways in which Native Americans in the San Francisco Bay area adopted, adapted, and rejected Catholicism during the Spanish colonial period. It was published by the University of New Mexico Press in 2009. Newell is currently working on a book manuscript entitled Marginal Mormons, which analyzes the religious experiences of nineteenth-century African American and Native American members of the Church of Jesus Christ of Latter-day Saints.