Walter rose to prominence in Uri. He became one of Uri’s representatives to the Swiss diet in 1431 and became the Landammann of Uri in 1434. He was the third Zumbrunnen man to serve as landammann. He remained in the role until 1437 or 1438.
He was involved in a couple major actions as Landammann, including a treaty between the communities of Lucerne and Nidwalden over fishing rights in Lake Lucerne. In 1435, he made a major war loan to Lucerne. According to the records, he personally delivered the loan (in gold coins).
He married Idda von Bramberg, said to be of an illustrious family from Lucerne. He owned land in both Schattdorf (presumably inherited from his mother Hemma Fürst) and in Attinghausen. Walter and Idda made a major donation to the St. Andreas Church in Attinghausen to establish a sort of religious-charitable foundation (the exact nature is unclear to me). They are thus recorded in the Necrology of the St. Andreas Church.
He died sometime after 1439. Walter is the first Zumbrunnen man to have an entry in the modern online version of the Historical Dictionary of Switzerland (in German), although earlier generations were included in the old print versions.
Name: Walter Zumbrunnen
Residence: Attinghausen and Schattdorf
Offices: Landammann 1434-38; diet representative 1431-39.
Death: After 1439