Francis T. Duffau, soldier and merchant, was born on July 10, 1808, in Albany, New York. After receiving a diploma from the Medical Society of Ostega County, Milford, New York, Duffau moved to Vicksburg, Mississippi, and early in April 1836 joined a volunteer cavalry company organized by John A. Quitman at Natchez, Mississippi, for service in the Texas Revolution. Duffau was a member of the Quitman company from April 5 to about May 15 and was among those who decided to remain in the Texas army after independence. After being honorably discharged on December 22, 1837, he settled in Houston, where he taught school, operated a grocery and baking business in partnership with J. T. Rendal, and practiced law. He moved to Austin in 1841 and worked in the General Land Office. He served as a private in the campaigns against Rafael Vásquez and Adrián Woll in 1842 and afterward settled in Milam County, where he was county clerk from 1846 to 1850.
Duffau moved back to Austin, married Mary G. Davidson on December 17, 1850, and went into the drug business with George H. Gray, Jr., in February 1851. In April 1852 he acquired full ownership of the business. He was Austin city recorder during the greater part of the 1850s. Sam Houston appointed him a trustee of the Deaf and Dumb Institute (now the Texas School for the Deaf) on December 29, 1859, and made him aide-de-camp to the commander of the Fourteenth Division, Texas Militia, on November 1, 1860. On September 12, 1863, Duffau was appointed to receive from the quartermaster the ammunition allotted to Travis County for home defense.
Duffau was affiliated with a wholesale drug firm in Galveston in 1866, but in early 1870 he was back in Austin in the drug business with Benjamin H. Thompson. He was a member of the Sons of Temperance in both Cameron and Austin, a charter member of the Independent Order of Good Samaritans, a charter vestryman of the Episcopal Church, and a Masonic officer. In 1871 he suffered from dropsy. He died in Bell County on December 14 of that year and was buried in Austin on December 16.