[2] During this time he suffered a heart attack but concealed it from physicians in order to avoid a discharge which he feared would prevent his acceptance for the priesthood.

Pius XII raised Griffin to Archbishop of Westminster, and thus ranking prelate in the Catholic Church in England and Wales, on 18 December 1943.

[4] Griffin was created Cardinal-Priest of San Gregorio Magno al Celio by Pius XII in the consistory of 18 February 1946.

His coat of arms is blazoned Gules issuant from a barrulet enarched in base a sweet william plant in pale Or supported by a Saint Bernard dog dexter and a griffin wings addorsed sinister Or, thus representing his full name.

On the 22 October 1960, Bernard's twin brother, Basil, laid the foundation stone of Cardinal Griffin Catholic College in Cannock, Staffordshire.