Peter W. Gray was born in Fredericksburg, Virginia, on December 12, 1819, to William Fairfax Gray and Mary Stone. The family moved to Houston, Texas, in 1838, and Gray opened a legal practice there. He became Houston's District Attorney in 1841 and served as one of the city's alderman. He was elected to the state legislature in 1846 and became a state senator eight years later. He served in the Texas Secession Convention during the winter of 1860-1861 and voted in favor of secession. He won a seat in the Confederate Congress in November 1861. He resumed his legal practice in Houston after the war, and he was appointed to the Texas Supreme Court in 1874. Poor health, however, forced him to resign a few months later, and he died of tuberculosis on October 3, 1874.