Born on December 20, 1813, to a wealthy Maryland family, Samuel Kirkwood became famous as the governor of Iowa during the Civil War. In 1823 young Samuel was sent to Washington, D.C., for four years to study Latin and Greek. He then taught for a year and worked as a drug clerk. He returned to his family, however, after they suffered a number of financial reversals. The Kirkwood family then settled in Richland County, Ohio, and Samuel Kirkwood spent some time clearing land for a new farm and occasionally teaching. He moved to the county seat in 1841 and two years later, after studying law, he was admitted to the bar.
In 1855, Kirkwood moved to Iowa at the urging of his wife. A year later he became a member of the Iowa Senate, serving until 1859. He was governor of Iowa from 1860 to 1864 and from 1876 to 1877. Kirkwood declined appointment as minister to Denmark in 1863 because he wanted to run for the United States Senate. He was appointed to complete the unexpired Senate term of James Harlan, who accepted the position of secretary of the interior.
Kirkwood was reelected governor and later returned to the United States Senate after the 1876 election. He too was appointed secretary of the interior, but resigned in 1882. In 1886 he was an unsuccessful candidate for Congress. He died on September 1, 1894.