Pétur was the son of Sigurgeir Sigurdsson who later became Bishop of Iceland and Gudrún Pétursdóttir.

He undertook a master's degree at the Lutheran Theological Seminary at Philadelphia in Philadelphia and studied journalism, English and Biblical Studies at Stanford University, California.

In 1947, he was ordained priest and served in the parish of Akureyri.

On October 1, 1981 he was elected as Bishop of Iceland.

This article about an Icelandic Lutheran bishop is a stub.