He gained the rank of captain in the service of the Royal Artillery (RARO).
He was a Knight of Obedience, of the Sovereign Military Order of Malta.
He married Selina Gerth van Wijk on 20 July 1939.
They had the following children: His eldest son, Frederick (9 June 1940 – 14 June 2011), also known as Fra' Fredrik Crichton-Stuart, was Grand Prior of the Sovereign Military Order of Malta Grand Priory of England.
Una Voce actively promotes and encourages the use of and petitions for wider indults in facilitating the traditional Tridentine Mass in the Catholic liturgy.