This shire knight was the second of four successive Gilbert Debenhams. His father, an able lawyer who served as a j.p. from 1349 until 1361, was retained as legal counsel to the Black Prince (from whom he received an annual fee of £5), to Robert de Ufford, earl of Suffolk, and to the prince’s chief councillor Sir John Wingfield (d.1361) of Wingfield.
Details of Debenham’s career suggest that he followed his father in his choice of profession, but, lacking his father’s ability, he does not appear to have attracted clients from among the higher nobility on a regular basis. As compared with his father and with his own son, he appears as a colourless individual. He was clearly reluctant to take on any responsibilities in local government: on 15 Oct. 1383 he obtained royal letters patent of exemption from service as a collector of taxes against his will, and on 16 Nov. he was exempted from appointment as sheriff. He put the first patent into use the following year, when, having been named as a collector of the subsidies granted in the Salisbury Parliament, he presented his exemption in Chancery in order to secure a discharge.
It is now impossible to ascertain where Debenham’s sympathies lay at the time of Richard II’s deposition, but there can be no doubt that he soon realized that his career could only benefit from acquaintance with Sir Thomas Erpingham, a staunch supporter of the new regime. In 1401 he assisted in making settlements of estates on Sir Andrew Butler and his wife Katherine, who was Erpingham’s niece, and these transactions brought him into contact with several prominent figures in the community of East Anglia. This stood him in good stead in the following year when he sought election to Parliament.
Debenham made his will at Little Wenham on 27 Aug. 1417, leaving bequests amounting to £5 10s. to the local church and to four other parishes. He died before 12 Oct., the date of probate, being survived by his wife Ellen, who subsequently married John Lancaster II.
