ˈæftɚɹ ˈɜːli ˌɛdʒuːkˈeɪʃən æt lˈʌdɡɹoʊv skˈuːl, kˈɪŋsmɪl ɐtˈɛndᵻd ˈiːtən ænd ðə ɹˈɔɪəl mˈɪlətˌɛɹi kˈɑːlɪdʒ, sˈændhɜːst, hiː dʒˈɔɪnd ðə ɡɹˈɛnɐdiɚ ɡˈɑːɹdz, hɪz fˈɑːðɚz ɹˈɛdʒɪmənt, ɪn nˈaɪntiːnhˈʌndɹɪd twˈɛnti.
After early education at Ludgrove School, Kingsmill attended Eton and the Royal Military College, Sandhurst, he joined the Grenadier Guards, his father's regiment, in 1920.