Thomas was the great-grandfather of U.S. President James K. Polk through the lineage of his daughter Lydia, who married Captain James Knox and gave birth to Jane Gracey Knox, mother of the President.

There, he married Naomi Thompson on January 1, 1745, in the "Valley of Virginia" with the ceremony performed by Rev.

John Craig, pastor of the Tinkling Spring Presbyterian Church in Augusta County, Virginia from 1740–1764.

On December 1, 1740, Thomas Glassbey (sic Gillespie) in Augusta County, Virginia received 400 acres on a draft of the north river of "Shanando" called the "Long Glade".

[8] Thomas Gillespie served in the Virginia Colonial militia in Augusta County in 1742.

[9][10] Before 1750, Thomas and his wife and young son, James, moved south to Anson County, North Carolina (in the area that became Rowan County, North Carolina in 1753), perhaps because of land that he acquired for his colonial militia service in Virginia.

Thomas, Naomi, and their first son (James) are reported to be the first white family to settle west of the Yadkin River in Anson County.

General Rutherford lived near Gillespie on Grants Creek[35] and was also a large land owner, like Thomas.

[8][36][37][38][39][40] Non-commissioned officers were entitled to receive 1,000 acres of land for their service in the American Revolution.

Thomas received Grants of 4,000 and 1,000 acres of land on Flat Creek, Duck River for his Revolutionary War services.

His son, George, also received bounty land in Sumner County, Tennessee for his service in the war.

[8] Flat Creek is a historic community that was established in 1799 in the extreme southeast corner of Williamson County, Tennessee.

It was founded primarily by Revolutionary War veterans awarded claims for their service.

After his death, his living children remained with the church until 1805 when there was a split in the congregation between revivalists and anti-revivalists.

However, his sons, Isaac, George, Thomas (Jr.), and David, took up residence in Williamson County in the early 1800s on the 5,000 acres that he obtained for his military service.

The following list shows the location of the 1,333 acres of land that Thomas Gillespie acquired in Greene and Washington Counties:[48][49] Thomas Gillespie died on December 13, 1796, in Rowan County, North Carolina, and is buried in the same grave and in the same coffin with his wife Naomi, who had died just hours before him, in the Thyatira Presbyterian Church Cemetery on Cathey's Creek in Mill Bridge, Rowan County, North Carolina.

It read as follows:[1][50] Seven of his eight sons were living at the time of his death: Isaac, George, Thomas, Alexander, David, John, and Robert.

He bequeathed the following to his wife and children in his will:[22] There are several descendants of Thomas Gillespie that have tested for DNA in his son George and Issac's families.