Sir Thomas Fettiplace was the third son of John Fettiplace, citizen and draper of London and Lord of the Manor of East Shefford (Berkshire), by his wife, Joan Fabian, widow of Alderman Robert Horne. His father died when he was a toddler. He would have been brought up in East Shefford and at Antwicks in Letcombe Regis by his mother and and step-father, John Estbury. 

Thomas was probably introduced to the Royal Court of King Henry VII by his elder brother, Anthony. Though he quickly rose above him in Royal favour and was knighted on 18th February 1504 at the time of Prince Henry's creation as Prince of Wales. By 1507,  commissions and appointments had brought him enough reward to begin purchasing manors across Berkshire and he made his home the beautiful old manor house of Compton Beauchamp. In 1517,  John Norreys, the nephew of Sir Thomas' wife, was fined for having murdered a certain John Enhold and his lands were confiscated. Thomas stood as trustee for his heirs and took on the manor of Ockwells in Bray as well. He must have stayed there often when attending the King at Windsor Castle.

Sir Thomas spent some time abroad serving his Sovereign in both military and political matters. In 1513, he had been "granted protection as he was about to serve in the Wars under Richard, Bishop of Winchester" in France.  Seven years later, he, together with the Lord Cardinal, the Privy Seal and other great nobility, was appointed one of the King's Council to make arrangements for the meeting of King Henry VIII and Francis I of France. Thomas was in attendance upon the King at the Field of the Cloth of Gold, when he and (the second) Lady Fettiplace were, with others, specially selected to attend upon Queen Catherine. A little later, he was appointed, together with his brother-in-law, Sir Nicholas Carew, and other relatives, to attend upon the King at his meeting with the Emperor Charles V at Gravelines.

Sir Thomas died soon afterwards seized of the manors of Stanford-in-the-Vale, Shrivenham, Bourton and Ockwells, all in Berkshire, as well as much other wealth. He was buried in "ye Abbaye Churche of Abingdon" and, by his will, he bequeathed a small sum of money to "ye Church of Lyttle Shifford to be bestowed ther after ye discretion of my nephew John FettypIace the elder on ye mending of my Grandmother's tombe or otherwise''. 

Sir Thomas had twice married, first to Margaret (alias Elizabeth), the daughter of Sir William Norreys of Yattendon (Berkshire) and, secondly, to Elizabeth, a sister of Sir Nicholas Carew, Master of the Horse, who, like Sir Adrian Fortesque, his brother Anthony's brother-in-law, lost his head on the block at the command of the Sovereign in whose favour he and Sir Adrian had once stood so high. By his second marriage, Sir Thomas left an only daughter, Katherine. Though his widow was pregnant at the time of his death, their baby son only lived a few months. Katherine Fettiplace married Sir Francis Englefield of Englefield House, the Master of the Court of Wards and Liveries to Queen Mary. When he fled abroad and his lands were confiscated during the reign of Elizabeth I, Katherine was regranted the use of her old family home at Compton Beauchamp, until her death in 1579.