Sørenssen received his candidate.theol. in 1785. He worked as a teacher in his home town of Christiansand and in Strømsø in Drammen, before in 1797 he became a priest in Risør. In 1804, he was the most important priest in Christiansand.
On 11 April 1811, he was invited to be bishop of Christiansand, and Sørenssen was the last Norwegian bishop to be ordained in Copenhagen.
The bishopric covered Agder and Rogaland at that time. He was a representative at the first two Stortings, and was also a politician from 1814 to 1817.
He did not have a special interest in politics, and did not speak at the Storting"s meetings From 1823 to 1845, he was bishop of Akershus, which is now the bishopric of Oslo, Hamar and Tunsberg, up to Telemark.