Teillier was born in Santa Bárbara, Biobío Region, on October 29, 1943.
He joined the Communist Youth in 1958, serving as regional secretary in the cities of Temuco and Valdivia. He then became regional secretary in Valdivia, where he was caught in the 1973 Chilean coup d'état. In 1974, he held the same post in Concepción and Lota.