Metcalfe designed the first coinage of the Irish Free State in 1928.
The first Irish coin series consisted of eight coins.
The Harp was chosen as the obverse.
Metcalfe was chosen out of 6 designers as the winner of the reverse design of the Irish Free States Currency.
The Horse, Salmon, Bull, Wolf-Hound, Hare, Hen, Pig and Woodcock were all on different denominations of coinage that was known as the Barnyard Collection.

Metcalfe's design based on the Trinity College harp was adopted as the basis for the Great Seal of the Irish Free State in 1923 and has remained the model for all official representations of the harp emblem on seals of state, Irish coinage and the coat of arms.

As a result of the war from 1914–18, the price of silver grew dramatically, until in 1920 the coins were worth more than the actual silver.
Therefore, a degrade silver coinage was issued containing only fifty per cent silver.
in 1935, it was George V's jubilee, and to celebrate the occasion, a crown piece containing a new design was issued.
The reverse side of the coin depicts an image of St George on a horse, rearing over a dragon.
Due to its modernistic design by Metcalfe it has earned little credit from collectors.

In 1936 Metcalfe designed the obverse crowned effigy of Edward VIII for overseas coinage which was approved by the King, but none were minted for circulation before Edward's abdication in December of that year.

Metcalfe was immediately assigned to produce a similar crowned portrait of King George VI for overseas use.
This image was also used as part of the George Cross design in 1940.
The George Cross is second in the order of wear in the United Kingdom honours system and is the highest gallantry award for civilians, as well as for members of the armed forces in actions for which purely military honours would not normally be granted.
It also features the flag of Malta in recognition of the island's bravery during the Siege of Malta in World War II.
Metcalfe also designed the Great Seal of the Realm.
He produced designs for coinage of several countries including Ireland and Australia.
He created a portrait of King George V which was used as the obverse for coins of Australia, Canada, Fiji, Mauritius, New Zealand and Southern Rhodesia.

To commemorate the extraordinary visit that George VI and Queen Elizabeth set out on to North America in 1939, three series of medallions were designed for the Royal Canadian Mint.
The reverse side of the coins contained a joint profile of George VI and Queen Elizabeth, which was designed by Percy Metcalfe.
This design was also used on the British Coronation Medal of 1937.

Metcalfe created a British Jubilee crown piece, which was exhibited in the Leeds College of Art in November 1946
Metcalfe designed the first coinage of the Irish Free State in 1928. The first Irish coin series consisted of eight coins. The Harp was chosen as the obverse. Metcalfe was chosen out of 6 designers as the winner of the reverse design of the Irish Free States Currency. The Horse, Salmon, Bull, Wolf-Hound, Hare, Hen, Pig and Woodcock were all on different denominations of coinage that was known as the Barnyard Collection.
Metcalfe's design based on the Trinity College harp was adopted as the basis for the Great Seal of the Irish Free State in 1923 and has remained the model for all official representations of the harp emblem on seals of state, Irish coinage and the coat of arms.
As a result of the war from 1914–18, the price of silver grew dramatically, until in 1920 the coins were worth more than the actual silver. Therefore, a degrade silver coinage was issued containing only fifty per cent silver. in 1935, it was George V's jubilee, and to celebrate the occasion, a crown piece containing a new design was issued. The reverse side of the coin depicts an image of St George on a horse, rearing over a dragon. Due to its modernistic design by Metcalfe it has earned little credit from collectors.
In 1936 Metcalfe designed the obverse crowned effigy of Edward VIII for overseas coinage which was approved by the King, but none were minted for circulation before Edward's abdication in December of that year.
Metcalfe was immediately assigned to produce a similar crowned portrait of King George VI for overseas use. This image was also used as part of the George Cross design in 1940. The George Cross is second in the order of wear in the United Kingdom honours system and is the highest gallantry award for civilians, as well as for members of the armed forces in actions for which purely military honours would not normally be granted. It also features the flag of Malta in recognition of the island's bravery during the Siege of Malta in World War II. Metcalfe also designed the Great Seal of the Realm. He produced designs for coinage of several countries including Ireland and Australia. He created a portrait of King George V which was used as the obverse for coins of Australia, Canada, Fiji, Mauritius, New Zealand and Southern Rhodesia.
To commemorate the extraordinary visit that George VI and Queen Elizabeth set out on to North America in 1939, three series of medallions were designed for the Royal Canadian Mint. The reverse side of the coins contained a joint profile of George VI and Queen Elizabeth, which was designed by Percy Metcalfe. This design was also used on the British Coronation Medal of 1937.
Metcalfe created a British Jubilee crown piece, which was exhibited in the Leeds College of Art in November 1946
Percy Metcalfe