He was the son of Sir Reynold Cobham by Joan, the daughter and heir of William de Evere.
This Reynold was the second son of John de Cobham, by his first wife Joan the daughter of William Fitzbenedict.
By 1334 he was a knight in the household of King Edward III and fought in the Scottish campaign against David de Bruce and then on the continent in the Low Countries and Brittany.
In 1346 he was in the force under Edward III that attacked France, fighting at the Battle of Crécy and the protracted but eventually successful Siege of Calais.
[1] Reynold married Joan Berkeley by whom he could claim to be related to the noble families of Sutton, Dudley, Beauchamp, De Despencer and Mortimer.