After his ordination to priesthood, he was sent to University of Rostock (rector of which was then David Chytraeus). After his studies he became 1578 headmaster of the school in Gävle. 1583 he was consecrated as bishop together with Petrus Benedicti, Nicolaus Stephani, and Christian Agricola with catholic ceremonies of the liturgy of John III. Soon after their episcopal consecration, these bishops had to sign a commitment to new Church Order (Nova Ordinantia), king John's liturgy, medieval tradition of church music and to use of some specific episcopal ceremonies, in addition to emphasis on study of Church Fathers. King John even planned sending Sorolainen to Constantinople for ecumenical dialogue with Orthodox Church. This dialogue was already formerly initiated by Tübingen theologians with Patriarch Jeremias II of Constantinople. Later in Synod of Uppsala (1593), bishop Sorolainen together with Bishop Olaus Stephani Bellinus made secretly CalvinistDuke Charles his enemy by initiative of banning Calvinism in Sweden, which was decided by the synod. When Duke Charles became Regent, after his War against Sigismund, son of his brother John III, he used his opportunity to revenge to Bishop Sorolainen by imprisoning him for alleged "popery", which was although annulled by Diet of Lingköping. 1609 King Charles seems to have forgotten his earlier anger and distrust to Sorolainen.
Sorolainen was also a noted writer, publishing his first work in 1614. He translated into Finnish the service book of 1614, wrote a large catechism (1614). Between 1621 and 1625 he published a book of sermons in Stockholm entitled Postilla.