During the Civil War, he rose to the rank of colonel in the Confederate Army and commanded Terry's Texas Rangers for a brief period before his death in 1862.

After working for a time with Samuel May Williams and Thomas F. McKinney, Lubbock joined the Texan Santa Fe Expedition as a lieutenant of one of the military companies.

Lubbock and his men were among the Texans who followed Alexander Somervell back to Texas on December 19, 1842, after declining to join William S. Fisher on the Mier Expedition.

At the beginning of the American Civil War, he accompanied Benjamin Franklin Terry, John A. Wharton, Thomas J. Goree, and James Longstreet (who was to become the commander of I Corps of Robert E. Lee's Army of Northern Virginia) from Galveston, Texas, to Richmond, Virginia.

While in Virginia, Lubbock, Terry, and some 15 other Texans organized themselves into an independent band of rangers to scout for the Confederate Army.

Lubbock was still a civilian in Virginia at the time of the battle of First Bull Run; he "exposed his life in bearing messages during the contest."

On January 8, 1862, Lubbock, then sick in bed in a Bowling Green hospital with typhoid fever, was promoted to colonel and advanced to command of the regiment.