Kammala jumla mai zuwa: A Yaƙin Duniya na Biyu, a matsayin Babban Kwamandan, Jirgin Ruwa na Bahar Rum, Cunningham ya jagoranci sojojin ruwa na Burtaniya zuwa nasara a cikin manyan yaƙe-yaƙe na Bahar Rum. Wadannan sun hada da
kai hari kan Taranto a cikin 1940, na farko da aka fara kaiwa jirgin ruwa a cikin tarihi, da kuma yakin Cape Matapan a 1941. Cunningham ya mallaki tsaro na layin samar da kayayyaki na Bahar Rum ta hanyar Alexandria, Gibraltar, da kuma mahimmin maɓallin Malta. Ya kuma ba da umarnin tallafin jiragen ruwa don manyan manyan jiragen ruwa na Allied a yammacin tekun Bahar Rum. A lokacin kaka na 1943, tare da wanda ke aiki, Sir Dudley Pound, ya mutu, Cunningham ya ci gaba da zama na farko na Sea Lord, shugaban kwararru na Royal Navy, matsayin da ya rike har zuwa lokacin da ya yi ritaya a 1946. An ɗaukaka shi a matsayin Baron Cunningham na Hyndhope a cikin 1945 kuma ya zama Viscount Cunningham na Hyndhope a shekara mai zuwa. Bayan ya yi ritaya, Cunningham ya ji daɗin matsayi da yawa, ciki har da Lord High Steward a bikin nadin Sarauniya Elizabeth II a 1953. Ya mutu a ranar 12 ga Yuni, 1963, yana da shekaru 80.