Sam Brannan (1819-1889) was California pioneer, businessman, journalist, and early member of The Church of Jesus Christ of Latter-day Saints.

Sam Brannan was born on 2 March 1819 in Saco, Maine, to Thomas and Sara Emery Brannan. He moved away from home to Ohio when he was 14 years old, and there learned about the Church of Jesus Christ of Latter-day Saints. He was baptized a member the Church in 1842.

Brannan was called to work as a printer in Connecticut with William Smith, brother of Joseph Smith. In 1844, the printing operation moved to New York City, and they started to print "The Prophet" (later "The New-York Messenger"), a newspaper for the Latter-day Saint Church. After Joseph Smith's death in June 1844, Brannan advocated for William Smith to take over as leader of the Church. This brought about Brannan's and Smith's disfellowship from the Church. Brannan was later reinstated as a member in 1845.

During the exdous of the Saints to the West, Brannan chartered the ship "Brooklyn" and persuaded leaders of the Church to use the ship to evacuate members of the Church from the eastern United States to upper California. The ship set sail via Cape Horn in January 1846, and arrived at Yerba Buena (near present-day San Francisco) on July 31, 1846.

Brannan had dreams of colonization and success in California, and tried to persuade Brigham Young, the new leader of the Church, to move the Saints there to a settlement he called "New Hope." However, Young rejected Brannan's proposal in favor of settling in present-day Utah. Brannan fell out of favor with the Church and focused his efforts on his business and printing pursuits. He established the first newspaper in San Francisco, the "California Star," and ran one of the only stores in between San Fransciso and the California gold fields. He made a great deal of money, opened more stores, bought land extending to southern California and Hawaii. Brannan became California's first millionaire, and held several public offices in San Francisco and California, including State Senator in 1853.

Brannan was accused of pocketing tithes given him by California Latter-day Saints, and was apostle Amasa Lyman was sent to collect $10,000 of owed tithing from Brannan. This, along with involvement in a group of vigilantes in California, led to Brannon being disfellowshipped, again, from the Church in 1851.

Later in life, Brannan left San Francisco in serious debt and began acquiring land in Mexico, in the State of Sonora, in the 1880s. He used money earned in Mexico to pay off debts in San Francisco. However, Brannan died in 1889 at age 70 in Escondido, California, after years of alcoholism and issues with his bowels, and had no money or relations left to his name.