In two volumes of memoirs, he recounted his memories of the Council House Fight in 1840 (in which the family's cook saved his life), the evacuation of the city during the incursion by Gen. Rafael Vásquez in 1842, and his father's return from the prison at Perote, Veracruz, in 1843.
At the outbreak of the Civil War in 1861, Maverick enlisted in Company B of the First Texas Mounted Rifles under Col. Henry E. McCulloch, but the unit saw insufficient action to satisfy him.
At Fort Donelson, Tennessee, he swam the Cumberland River and set fire to a Union gunboat, for which feat he was commissioned a Second Lieutenant.
After the war, Maverick returned to San Antonio, where he farmed on the land that now makes up Brackenridge Park, north of downtown.
He died in Austin February 27, 1936, at the age of ninety-eight, the last survivor of Terry's Texas Rangers, and was buried at Mission Burial Park in San Antonio.