Sieveking was born in the Chilean city of Rengo (in the O'Higgins Region) on September the 7th of 1934. He performed as an actor on theatrical productions by Instituto del Teatro (Chile’s Theatre Institute), Teatro de la Universidad Católica (the Catholic University Theatre), Teatro del Ángel (Angel Theatre Company) and Teatro Itinerante (Itinerant Theatre). He worked together with Víctor Jara on a number of theatrical and musical projects, including in his album: “La Población” – in which he co-wrote the song “Herminda de la Victoria” with Jara. 
He was one of the founders of the Teatro del Ángel (Angel Theatre Company) in Chile and in Costa Rica, where he settled and worked as a political exile. In 1974 he is awarded the “Casa de Las Américas” prize for his “Pequeños animales abatidos” (Small game hunt).
Today, in addition to holding university posts and being involved in television projects, he is vice-president of the Academia Chilena de Bellas Artes. (Chilean Academy of Fine Arts)
His most important theatrical work have been:
- "Mi hermano Cristián" 
- "La madre de los conejos" 
- "Parecido a la felicidad" 
- "Ánimas de día claro" 
- "La remolienda"  (the brothel)
- "Tres tristes tigres" 
- "Todo se irá, se fue, se va al diablo" 
- "La mantis religiosa" (The praying mantis) 
- "Manuel Leonidas Donaire y las cinco mujeres que lloraban por él" (Manuel Leonidas Donaire and the five women who cried for him” 
- "Cama de batalla" 
- "La virgen de la manita cerrada" 
- "Ingenuas palomas"