Richard Edgcumbe was the eldest son of Sir Peter (or Piers) Edgcumbe (1477 – 14 August 1539) of Cotehele, Cornwall, and his first wife, Jane Derneford (d. before 1525), daughter and heir of James Derneford of Stonehouse, Devon, and widow of Charles Dynham of Nutwell, Devon.

He was among the knights created by Edward Seymour, 1st Earl of Hertford, 18 October 1537, and two years later he succeeded to his father's estates.

On a portion of the Stonehouse property, which had come into the family through his mother, and which Sir Piers had already emparked, he built the house named by him Mount Edgcumbe, which was completed in 1553.

He prided himself on his housekeeping, taking care to always have in hand two years' provision of all things necessary for himself and his family, and he kept in a chest for current needs a sum of money which he never allowed to fall below £100.

[3] Edgcumbe married firstly, about 1516, Elizabeth Arundell, the daughter of Sir John Arundell (c. 1474 – 8 February 1545) of Lanherne, Cornwall, by his first wife, Lady Eleanor Grey, the daughter of Thomas Grey, 1st Marquess of Dorset, and his second wife, Cecily Bonville, 7th Baroness Harington.