John Mullen, farmer and Confederate officer, was born in New Castle County, Delaware, on January 20, 1811. On January 21, 1836, Mullen married Mary Hamilton of Butler County, Ohio, in Terre Haute, Indiana. This couple had two sons and three daughters. In 1842 Mullen was a member of the Mier expedition to Mexico and eventually he was among the survivors incarcerated at Perote Prison. Though many died in prison, Mullen endured and was among those released on September 16, 1844, and put on board a ship bound for Galveston.
With the onset of the Mexican War in 1846, Mullen volunteered and was mustered at Fort Clark, Indiana, as a second lieutenant in Company H of the Fourth Indiana Volunteer Regiment. This unit participated in several engagements during the course of the war. On July 16, 1848, Mullen was discharged as a colonel at Madison, Indiana.
In 1849 Mullen brought his family to Texas and settled at Webberville in Travis County. In February 1853 the Mullens relocated near Florence in Williamson County and began farming. After the start of the Civil War, Mullen enlisted in the Twentieth Texas Infantry Regiment on April 2, 1862. Later, he organized two companies to be added to the Second Texas Cavalry, Arizona Brigade, with which he served as lieutenant colonel. On January 19, 1863, Mullen was discharged on account of disability by order of Gen. John Magruder. On December 15, 1863, Mullen's wife Mary passed away and was buried in the Mullen Cemetery near Florence. Mullen returned to the military in 1865 and was listed on the rolls of the Eighth Texas Cavalry Regiment of Col. Benjamin Terry's “Terry's Texas Rangers."
After the war, Mullen settled in Burnet County, Texas, where he remarried on January 23, 1866. His new wife, Ruth M. Fisher of Arkansas, gave birth to a daughter before she died in 1869. Two years later, on February 9, 1871, Mullen married Nancy A. Mowery (born on September 4, 1836) of Missouri. The couple had one son and two daughters before John W. Mullen died on January 9, 1894. He is buried in the Mullen Cemetery.