Born on May 8, 1833 in Providence, the son of Dr. Francis L. Wheaton and Amelia S. (Burrill) Wheaton, Frank attended public schools and studied engineering at Brown University for one year before leaving college to accept a position with the United States and Mexico Boundary Commission. This agency, headed by Rhode Islander John Russell Bartlett, set the boundary between the two recent combatants in the Mexican War.
After five years service with the Commission, Wheaton accepted an appointment as a first lieutenant in the U.S. Cavalry. As a young officer, he engaged in several skirmishes with the Native Americans of the Southwest. On March 1, 1861, preceding the outbreak of Civil War, Wheaton became a captain in the 4th Cavalry and in July the lieutenant colonel of the 2nd Rhode Island Infantry under Ambrose Burnside. Commended for “admirable conduct” at First Bull Run, Wheaton fought with the 2nd Rhode Island in the Virginia Campaigns of the Army of the Potomac rising to the rank of brigadier general commanding a brigade in the Sixth Corps. He fought at Fredericksburg, Gettysburg, the Wilderness, Cedar Creek, Spotsylvania, Cold Harbor, and Petersburg.
In July 1864, Wheaton, now commanding a division, was rushed by water to Washington to repel a threatened attack on the national capital by Confederate General Jubal A. Early. His repulse of the attackers earned Wheaton a brevet as major general. His final battle was the successful assault on Petersburg in April, 1865.
At war’s end Wheaton was mustered out of the volunteer service and secured an appointment as lieutenant-colonel in the regular army. At this time he received an honorary degree from Brown University and was presented with a sword of honor by the state of Rhode Island.
Returning to the West, Wheaton successfully commanded the 1872-73 expedition against the Modoc Indians in Oregon and northern California. He was made a brigadier general in 1892 and assigned to command the military Department of Texas.
In 1897, Wheaton was promoted to his old volunteer rank of major general and retired. Thereafter, he made his home in Washington, the city he had defended so effectively in July, 1864. At his death on June 18, 1903, General Wheaton was survived by his wife and two daughters.