Born in 1925 in Plouider, he only discovered the French language at the age of 7.
After studying at the college in Lesneven, he entered the major seminary in Quimper in 1944 where he acquired excellent musical training.
A priest in 1949, he was appointed to the island of Sein for a year. There he discovered a deeply moving repertoire written especially for the islanders who sing it on Good Friday, the day when no one goes to sea.
His future was mapped out: ten years in Landivisiau, twenty-five in Morlaix, twenty in Carantec, he was a pioneer in the renewal of Breton music in the service of the Church.
In Landivisiau he created the Kanerien Bro Leon choir which won first prize in the national choir competition in Paris. The opening to secular singing is badly perceived and he loses the title of choirmaster. He created a new choir in Morlaix, Kanerien Sant Vaze. He arranged many Breton hymns and songs, but also opened up to classical music: the choir won first prize in the international competition for the best recording in 1964 with Haëndel’s Judas Macchabée.
That same year, he created with Georges Le Coz the first men’s choir in Brittany. Encouraged by the liturgical reform, he composed a mass entirely in Breton, Oferenn war gan.
The Ensemble Choral du Léon, created in 1968 with Georges Le Coz, opened the first festival of Le Relec in 1971, because Roger Abjean is also sensitive to the built heritage. His meeting with Eliane Pronost was decisive. He accompanied her with the Quatuor du Léon for many years during which time there were concerts, recordings, discs (over 60) and publications. His last assignment took him to Carantec in 1985.
He was made a Knight of the Legion of Honor in 2005. He also received the collar of the Order of the Ermine in 2008.