He was the third child of Duke John I, from his marriage Agnes of Lindow-Ruppin.

After his father's death in 1392 or 1393, he ruled jointly with his brothers John II and Albert I (d. 1397).

Ulrich received the Lordships of Neubrandenburg, Stargard, Strelitz and Wesenberg.

He was buried in the Wanzka convent in Blankensee, where his daughter Anna was abbess.

Ulrich I married Margaret, the daughter of Duke Swantibor III of Pomerania-Stettin.