In 1826 he graduated from the United States Military Academy at West Point, NY. As a US Army officer, he was assigned to posts in New York and Missouri. He served in the Black Hawk War in 1832. After resigning his US Army commission in 1834, he returned to Kentucky to care for his dying wife.
He moved to Texas in July of 1836 and enlisted in The Republic of Texas Army. One month later he was appointed to the position of Adjutant General and in January of 1837, he became Senior Brigadier General in Command of the Republic Army. The Second President of the Republic of Texas, Mirabeau B. Lamar, appointed him Secretary of War in December of 1838. In 1840, he returned to Kentucky and married Eliza Griffin in 1843. They settled in China Grove, TX on his large plantation and lived there until 1849.
During the Mexican-American War, he commanded a company of Texas Volunteers. Later as a Colonel in the United States Army, he served on the Texas frontier and in the West. At the outbreak of the American Civil War, he resigned from the US Army and was appointed a General by President of the Confederate States of America Jefferson Davis.
He was killed at the Battle of Shiloh in 1862 and was buried in New Orleans, Louisiana. In 1866, a joint resolution of the Texas Legislature was passed to have his body reinterred to the state cemetery in Austin (the re-interment occurred in 1867). Four decades later, the state appointed Elisbet Ney to design a monument and sculpture of him to be erected at his gravesite.
The Texas Historical Commission has erected a historical marker near the entrance of what was once his plantation. An adjacent marker was erected by the San Jacinto Chapter of the Daughters of The Republic of Texas and the Lee, Roberts, and Davis Chapter of the United Daughters of the Confederate States of America.