Werkström was a hospital priest in Sundsvall between 1964 and 1970 and Rector of Sköndalsinstitutet between 1970 and 1975. He became the royal chief predictor in 1974. In 1975 he was elected Bishop of Härnösand, a post he kept till 1983 when he was elected Archbishop of Uppsala and Primate of Sweden. He retired in 1993. He died in 2010 after a long-term illness.