Soames was the son of Captain Arthur Granville Soames, descendant of a brewing family which became part of the landed gentry, by his wife Hope Mary Woodbine Parish. His parents divorced early on, and his mother remarried the 8th Baron Dynevor (descendant of the 1st and last Earl Talbot) as her second husband, by whom she had issue including Richard Charles Uryan Rhys, 9th Baron Dynevor.
Christopher Soames married Mary Churchill (the youngest child of Winston Churchill) on February 11, 1947 after military service in World War II. They had five children, of whom the best known is his eldest son Nicholas Soames MP, the former Conservative Shadow Secretary of State for Defence.
Before entering politics, he served as the Assistant Military Attaché in Paris. He served as the Conservative M.P. for Bedford (1950-1966). Soames served in the Cabinet of Harold Macmillan as Secretary of State for War from 1958 to 1960 and Minister of Agriculture, Fisheries and Food from 1960 to 1964 under Macmillan and his successor Alec Douglas-Home.
In 1968 Harold Wilson named Soames the British Ambassador to France, where he served until 1972. He was Vice-President of the European Commission from 1973 to 1976. He was created a life peer, becoming Baron Soames, of Fletching in the County of East Sussex in 1978, and served as the interim Governor of Southern Rhodesia (1979 to 1980 between the Lancaster House Agreement and that country gaining independence as Zimbabwe. From 1979 to 1981 he was Conservative Leader of the House of Lords and thus a minister in Margaret Thatcher's government concurrent with his duties in Rhodesia.
He died from pancreatitis aged 66 and is buried within the Churchill plot at St Martin's Church, Bladon, near Woodstock, Oxfordshire.