Miles Stapleton was the eldest son of Sir Nicholas Stapleton, a royal justice, and Margery Basset. He was married firstly, before 1286, to Sybil (also called Isabel), daughter of John de Bellew and Ladereyna, who was probably descended from the elder line of the Bruces. After her death before August 1301 he married Joan Tyndale. Miles served under King Edward I in Gascony and Scotland in the 1290s. He is described in 1300 as a knight of the household of Henry de Lacy, earl of Lincoln and he accompanied the earl on a trip to the papal court. In 1303, Edward I appointed Stapleton to the Prince of Wales’ household as steward. His importance in his home county of Yorkshire was increased by the marriage of his eldest son to a daughter of John of Brittany, Earl of Richmond, and a grand-niece of the King, and his second son’s marriage to a daughter of Brian FitzAlan, Lord of Bedale, connecting him with two branches of the greatest family in Yorkshire. Between 1302 and at least 1307 Edward I made Stapleton Seneschal of Knaresborough Castle and Steward and joint Constable of Knaresborough Forest.
Following the death of Edward I, Stapleton became Steward to the new King’s Household and accompanied him in 1308 to Boulogne for the marriage to Isabel of France. However, the rise of Piers Gaveston as the King’s favourite meant Stapleton’s influence went into decline and he allied himself with Thomas, Earl of Lancaster. Stapleton and his family were pardoned in 1313 for any involvement in the death of Gaveston. In 1314, he was part of the army sent to relieve besieged Stirling Castle and he is listed in two of the chronicles as having been killed in the resulting battle.