Thomas was born on August 12, 1812 in Wilson, TN and died March 14, 1888 in Vernon County, MO. His father, Thomas, apparently died about the same time as he was born. He would have been about 11 years old when his mother Mary died and after that apparently stayed with his sister Rachel [Pentecost] Reed.

On October 31, 1835 Thomas married Sarah Davis in Wilson, TN. Thomas was a farmer and purchased quite a bit of land in Tennessee. The family was still there in the 1850 census but in 1852 Thomas bought land in Hickory County, MO.

Family legend has it that sometime between 1855 and 1860, his wife Sarah was killed by bushwhackers. No marked grave for Sarah can be found in Hickory Co. but a sister, Charity [Davis] Williams died in 1853 and is buried in Hermitage Cemetery, Hermitage, Hickory Co., so it is likely that Sarah was buried there also.

Wilson's History of Hickory Co. mentions Thomas Pentecost as a bridge commissioner in 1860. There is also much information on Thomas Davis, brother of Sarah and early settler in Hickory Co. John Siddle Williams, husband of Charity Davis, served as sheriff. The Williams home, built by slave labor in 1847, is now the Hickory Co. Museum and head-quarters of the Hickory Co. Historical Society.

In 1865, Thomas sold all of his property in Hickory County, MO and moved to Montgomery County, Illinois but returned to Vernon County, MO in 1870 and remained there until he died.