(Alexander Frank) Philip Christison was born in Edinburgh, on 17 November 1893, the eldest son of five children of Sir Alexander Christison and his second wife, Florence. He was educated at Edinburgh Academy and University College, Oxford.

Christison was commissioned into the Queen's Own Cameron Highlanders in 1914 and fought at the battles of Loos (for which he was awarded the Military Cross), the Somme, Arras during the First World War. In 1924 Christison was Assistant Manager of the British Olympic team in Paris. He was Commandant of the Staff College at Quetta [Pakistan] (1940-41). Christison was promoted Major-General in 1941 and Lieutenant-General in 1942. During the Second World War in 1943, Christison commanded Slim's 15th Indian corps in Arakan, in eastern Burma [Myanmar] where the rear of the Indian forces were encircled by 6,000 Japanese, but succeeded in winning a decisive victory, the first against Japanese forces. In 1945, Christison commanded the 14th army and also deputised for Sir William Slim as Commander of Allied land forces, South-East Asia during the latter's leave. After Slim's return, Christison commanded 15 Corps and led them into Rangoon in May 1945. In September 1945 he deputised for Admiral Lord Louis Mountbatten and took the surrender of the Japanese 7th Area Army and South Sea Fleet at Singapore. From 1946-6, Christison was Allied Commander of Netherlands East Indies [later Indonesia]. He retired in 1949 and farmed at Melrose, Roxburghshire, Scotland.

Christison was married twice: to Betty Mitchell, with whom he had two daughters and a son, from 1916 until her death in 1974; and then to Vida Wallace Smith until her death in 1992. He died in 1993.