He studied at Brasenose College, Oxford, later moving to Gloucester Hall, where he graduated with a Bachelor of Arts in February 1619.
[1] In 1624, Griffith became the rector of St Mary Magdalen Old Fish Street in London, possibly through his connection to John Donne.
[1] With the onset of the Civil War in 1642, Griffith regularly preached against the Parliamentarians who opposed the King, including in his criticism any who offered material or financial support to them.
This led to his arrest on 5 November, and he was imprisoned at Newgate and then at Lord Petre's house, which had been seized by anti-Royalist forces.
[1] He helped to defend Basing House, 1645; his royalist sermon (1660) answered by Milton, 1660; master of the Temple and rector of Bladon, Oxfordshire, c. 1661–5.