Sir August Bernard Tellefsen Cayzer, 1st Baronet, was his elder brother.

Cayzer was Chairman of the British & Commonwealth Steamship Company Ltd, of Clan Line Steamers Ltd and of the Union Castle Mail Steamship Company Ltd and also sat as Member of Parliament (MP) for Portsmouth South from 1918 to 1922.

[1] Cayzer stood for Portsmouth South again at the 1923 general election and was returned to Parliament, holding the seat until 1939.

Lord Rotherwick married Freda Penelope, daughter of William Hans Rathbourne, in 1911.

He died in March 1958, aged 76, and was succeeded in his titles by his eldest son Herbert.