He was named for his grandfather, Col. Charles Mynn Thruston, who served in the American Revolutionary War and in the Virginia General Assembly.

Their eldest son, William Sydney Thruston (1828-1864), fought for the Union Army as a captain of the 18th U.S. Infantry during the Civil War, but drowned after falling from a boat into the C&O Canal in June 1864.

In 1814, 16-year-old Thruston graduated from the United States Military Academy, and served during the War of 1812 as an engineer on Governors Island, New York City.

Volunteers, with military authority to protect the B&O Railroad from Confederate raiders such as McNeill's Rangers.

In April 1862, he resigned his commission and allowed a younger commander to assume the responsibility of protecting the B&O Railroad from the enemy cavalrymen.