Born in Nashville, Tennessee, Burnett also lived in Missouri and Oregon. In 1846, while in Oregon City, he converted to Catholicism, in part because of the influence of the published Purcell-Campbell debate. An editor and lawyer, he settled in California in 1848 and became active in state politics. He was elected the territory's first American, non-military governor and held the position as the region transitioned to statehood in 1850.
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