Gerald married, firstly, Margaret Rocheford, daughter of Sir John Rocheford. Their children included:
- Thomas FitzGerald, died before his father without issue.
- Lady Joan FitzGerald d. Jul 1452, married James Butler, 4th Earl of Ormonde , who claimed the Kildare title in right of his wife.
He married secondly, Agnes Darcy, daughter of Philip Darcy, 4th Baron Darcy de Knayth and Elizabeth Gray. Their children included:
He reputedly had one illegitimate son, Richard. He has been identified as Richard FitzGerald of Ballysonan, who married into the Castlemartin family, and was the ancestor of the Baron of Dunsany.
Since his only legitimate son predeceased him the title should have passed to his brother John, de jure 6th Earl, although his son-in-law, the Earl of Ormonde, also claimed the title in right of his wife, Joan. The dispute was eventually resolved in favour of John's son Thomas FitzGerald, 7th Earl of Kildare.[4]
- ^ FitzGerald, Walter. "The FitzGeralds of Ballyshannon", Journal of the Co. Kildare Archaeological Society and Surrounding Districts, Vol. 3, County Kildare Archaeological Society, 1902, p. 427
- ^ Otway-Ruthven, A.J. History of Medieval Ireland Barnes and Noble reissue 1993
- ^ Webb, Alfred. "Fitzgerald, Gerald, 5th Earl of Kildare", A Compendium of Irish Biography, M.H. Gill & Son, Dublin, 1878
- ^ Otway-Ruthven