Sumpter, was born in Owen County, Indiana, on February 21, 1827, where he worked as a farm boy in Indiana until 1844, when he moved to Illinois. 
He went on to enlist for service in the Mexican War in 1847 and was assigned to Company D, First Infantry regiment, commanded by Capt. Seth Eastman. 
Sumpter landed with his unit at Port Lavaca, Texas, in October 1848 and marched to Salado Creek, near San Antonio, where the government provided horses and made mounted infantry of three companies.  On March 1849 Capt. Sidney Burbank led three companies of the first infantry, including Sumpter, to the Rio Grande, where a camp at Eagle Pass (later Fort Duncan) was established. 
Sumpter's company was stationed at Fort Duncan, where they scouted for Indians and acted as escorts for provision trains between San Antonio and El Paso.
After his discharge as a sergeant on April 27, 1852, Sumpter decided to settle at Eagle Pass, which was then a fledgling frontier village adjoining Fort Duncan and the jumping-off place for California-bound gold seekers traveling the Mexico route. 
He tended bar for Henry Matson until 1854, when he opened a saloon of his own and then went into the cattle business. 
In 1872 Sumpter frequently acted as a deputy sheriff, and since the county was unorganized he had to accompany prisoners under perilous conditions nearly 150 miles to San Antonio in Bexar County. 
During the Civil War Sumpter became a merchant and was appointed by Lorenzo Castro as customs inspector for the Confederacy.  
When Maverick County was organized in 1871 he was elected the first county sheriff, an office he held until 1876. After leaving office he moved to Uvalde, where he lived for a time.  He returned to Eagle Pass in the early 1880s as commissary manager for a railroad-construction company, which was extending a line from Piedras Negras (across from Eagle Pass) into Mexico.
Sumpter was appointed United States customs inspector at Eagle Pass in 1894 and held the position until his death on November 20, 1910.