He grew up in Brest, where he was exposed to Breton language and culture.
His father's family had included several Brest mayors.
Malmanche continued his studies at the Collège Stanislas de Paris.
He studied law in Rennes and literature in Paris.
Malmanche performed his military service in an infantry regiment at Brest.
He worked with the railway, then in insurance, before establishing himself in Courbevoie as a master blacksmith.
In 1912, he married Jeanne Briantais.
He joined the army at Nantes in 1914, but later returned to Courbevoie to produce material for the army.In 1903, he started a Breton journal Spered ar vro; only four issues were produced.
From 1904 to 1905, he taught a class in the Breton language.