George M. Trowbridge was born April 6, 1833, at Houseville, Lewis County, New York, the son of Alanson Trowbridge and Mary ("Polly") Deming. In 1836, he moved with his parents to Delta, Ohio, where they worked as farmers. At the age of 16, George entered school in Perrysburg, Ohio. In 1859, he received his A.B. from Kalamazoo College, followed by his M.D. from the University of Michigan in 1862. On May 17 of that year he married Lesbia ("Lebbie") E. Fox (b. Nov. 26, 1837), the daughter of Daniel Fox and Sarah Dean, of Kalamazoo, Michigan. They had six children, including May (b. 1863), Perry (b. 1866), Lena (1866-1882), James (b. ca. 1870), D. Hector (1873-1950), and Hugh (1878-1880).
After graduation, Trowbridge began his medical practice in partnership with Dr. John Bennett (later Dean of the Cleveland Medical College) in Centreville, Michigan, but both men soon quit their civilian practices to respond to the call for volunteers to fight in the Civil War. Trowbridge entered the service as a contract surgeon in January 1863, and was commissioned in August as assistant surgeon of the 19th Michigan Infantry, remaining with the regiment through the end of the war. In the absence of a regimental chaplain, Trowbridge also unofficially filled this post for several months.
Trowbridge joined the 19th Michigan while they were stationed in east Tennessee. In the spring of 1864, however, the comparative calm of occupation duty was broken when the regiment was ordered into the Atlanta Campaign. At the Battle of Resaca, the regiment suffered heavily and lost their colonel, Henry C. Gilbert, but they continued under Sherman's command throughout the campaign, through the March to the Sea and the March through the Carolinas. Gilbert, the physician and caretaker, was deeply affected by the carnage and destruction of Sherman's campaigns, but, like many soldiers, argued that military necessity compelled their course of action. After the Battle of Goldsboro in March 1865, the regiment took part in the Grand Review of the Armies in Washington in May, and, a few weeks later, Trowbridge returned to civilian life. He and his wife settled first in Three Rivers, Michigan, but did not remain long, returning to Centreville early in 1867. He lived there until his death from illness on February 7, 1885, at the age of 51.