In 1861 he assumed by Royal licence the additional surname of Hamlyn, which was that of his father-in-law (see below).
In 1865 he was returned to Parliament for Hampshire South, a seat he held until November 1868.
Hamlyn-Fane married Susan Hester, daughter of Sir James Hamlyn-Williams, 3rd Baronet, in 1850, through which marriage Clovelly court, Clovelly, Devon, came into the Fane family.
Hamlyn-Fane died at his country seat, Avon Tyrrell, Hampshire, in December 1868, aged 51.
His wife only survived him by a few months and died at Clovelly Court in May 1869, aged 45.