In September 1945, Kellway was appointed Consul-General in New York.[2][3] Four years later, in September 1949, Kellway was named as the first Minister to Italy.[4] Kellway and his family left directly from New York for Rome in October 1949.[5] While Kellway was Minister to Italy his daughter Anne met Lieutenant Jeffrey Francis and was married in Rome, in 1953.[6][7]
Kellway was appointed Minister to Brazil in 1954.[8] While posted in Brazil, Kellway's wife was flown to New York for successful surgery, on the advice of physicians.[9]
Kellway retired to Bath, Somerset. He died on 14 June 1963.[10][1]