He is known to Galician intellectuals as "O vello profesor" ("The old professor"). He co-founded the Seminario de Estudos Galegos (with Fermín Bouza Brey and Lois Tobío Fernández) and was director of the Instituto Padre Sarmiento de Estudios Gallegos and the Museo de Pontevedra. With a deep interest in humanist culture, Filgueira Valverde completed extensive and informative work in a period in which this function was nonexistent or unfulfilled by institutions.
The Royal Galician Academy agreed to dedicate the 2015 Day of the Galician Letters to Filgueira Valverde for his work in favour of the Galician language and culture.
He is a figure that arouses controversy and yet plays a fundamental role in the recounting of Galician culture and literature of the 20th century.