He is notable for holding the office of Serjeant-at-law (Ireland) for more than twenty years until his death at the age of eighty-six.
[1] He was born in Tullycorbet, County Monaghan, a younger son of the Reverend Morgan Jellett (died 1832), rector of the parish, and Harriette Townsend Poole, daughter of Hewitt Baldwin Poole of Mayfield, County Cork and Dorothea Morris.
John Hewitt Jellett, Provost of Trinity College Dublin, was his elder brother.
[2] He went to school in Edgeworthstown, County Longford, and entered Trinity College, Dublin in 1840, when he was still only 15, graduating BA in 1846.
[4] Unusually, he remained Second Serjeant until his death at the age of eighty-six, although he seems to have ceased practising law about 1899.