A new Great Seal was required in 1927 when the Royal Style and Titles was amended to reflect the altered state of affairs arising from the foundation of the Irish Free State. New designs were considered by the Royal Mint Advisory Committee, which had been instituted in 1922 and its final recommendation found in favour of the strikingly modern artwork submitted by Percy Metcalfe.

During the 1920s and 1930s he established himself as a prolific numismatic artist, designing coins for several countries including the series introduced in 1928 for the Irish Free State and the United Kingdom crown of 1935 commemorating the Silver Jubilee of George V. He was also responsible for the Coronation Medal of 1937 and the crowned effigy of George VI used on a number of overseas coinages.

On the obverse the seated King is depicted holding the sceptre with the cross in his left hand and the sceptre with the dove in his right. The treatment of the inscription is unusual, consisting of a double band of lettering and beginning at the base rather than the top of the Seal. The reverse features a beautifully composed equestrian portrait of the King, with a trident and wave pattern below the horse indicating the nation's island status and great maritime history.