On 1 October 1919, he was married to Beatrice Eileen, daughter of James Meakin, Esq., of Westwood Manor, Staffordshire, and of the Countess Sondes. Lady Cayzer died in 1981.
From 1920 to 1921 he was an unpaid additional private secretary to the Secretary for Scotland, Robert Munro. In the 1922 general election he was returned as member for the City of Chester division of Cheshire, and represented the constituency until his death on 18 February 1940 aged 44. He and his butler were found dead from gunshot wounds, with a shotgun laying next to Cayzer.[2] He was buried at Newtyle Cemetery, Angus.[1] Cayzer predeceased his son (Nigel John), who died during the war on 11 September 1943, aged 22.[3]