Educated privately, with Henry Walter as a tutor, he entered St. John's College, Cambridge in 1836, and graduated B.A.
He succeeded on his mother's death to the family estate of Whatcombe, Dorset, and to landed property in the Isle of Purbeck in 1863.
[1] In 1876 Mansel-Pleydell was high sheriff of Dorset, and he was a member of the county council from its establishment in 1887 till his death.
[1] Mansel-Pleydell was the author of:[1] He also contributed papers on natural science and archaeology to the journals of learned societies.
His successor as the president of the Dorset Natural History and Antiquarian Field Club, Lord Eustace Cecil, donated a gift of £300.00.
The funds were combined in the Mansel-Pleydell & Cecil Memorial Trust, for the promotion of the study of natural history, archaeology and physical sciences in Dorset.
[6] Originally, a small cash prize and a silver medal were provided for the winners of two competitions: one focussing on natural history and archaeology, and one on chemistry.