Griffiths married three times: first Evelyn Krefting in 1949; and after her death in 1998 he married Heather Renwick Brigstocke, the former High Mistress of St Paul's Girls' School, on 22 January 2000. She was killed in a car accident in 2004. She had been created Baroness Brigstocke in 1990; they were one of the few couples who both held titles in their own right. In July 2009, he married Greta Fenston. He had four children by his first wife: three daughters and one son.[4]
In cricket, Griffiths was a fast bowler. At Cambridge University, he won Blues for cricket in 1946, 1947, and 1948, recording career-best figures of 6 for 129 against Lancashire in 1946. He also made eight appearances in the County Championship for Glamorgan, taking 4 for 61 against Surrey on his debut in 1946.[7] In all, he played 38 first-class matches, taking 102 wickets at an average of 31.47.[8]