He took a degree in Philosophy and Arts and works as a teacher of Secondary Education. In 1978 he got in touch with syndicalism and entered the Teaching Trade Union in Galicia, being the national secretary for five years. He has been an important member of the political party 'BNG' since it was founded and continues to be a member of the Galician Parliament since he entered in the third session. He took part in the Education and Culture and Fishing Commissions. Besides, he works in the City Council of A Coruña as spokesman of the 'BNG'.
Tello León resigned on 29th January 2002 to continue to be the spokesman of the 'BNG', being replaced by Tereixa Novo Arrojo.