In 1955 in Brest, Pierre Le Moine and other Breton nationalist founded the magazine Ar Vro and later Jeune Bretagne that became L'Avenir de la Bretagne; he was a regular contributor to Armor Magazine.
He was an original administrator of Kuzul ar Brezhoneg and continued for 20 years.
In 1949 he was a founding member of the Federal Union of European Nationalities (FUEN).[4] He was vice-president from 1980 to 1986, then president for Europe from 1986 to 1990.[5] He represented the FUEN at the Council of Europe for 17 years from 1990[6] and at the OSCE since 1992.
A Commander of the Order of St John (Denmark), he was also awarded the Order of the Ermine in 1994[7] and the Order of the European Combatant.
He was the president of the Menez Kamm, European Youth Center, opened in the property of Countess Vefa de Saint-Pierre. He was also the founder of the Brittany Regional Action Committee in 1961.
He was the inspiration for the Blue Book of Brittany, which, without him, could not have been written or published, as recorded by Louis Mélennec.