When reports of bombs falling first came in, he evacuated to his bomb shelter with his wife and children. The mayor was apparently corrupt, using taxpayer dollars to fund an extravagant nuclear shelter just for his family. After the bombs fell, a mob began to gather outside, demanding to be allowed in. The mayor, realizing the mob would soon break through, killed himself by dropping a radio into his bathtub, hoping that his body could be presented to appease the mob and allow his family to live. The mob, however, stormed the facility and killed his family, who were still unaware the mayor had committed suicide.
The Sole Survivior can use his access number, which is simply 123456, to the Boston Public Library in order to get an authorized entrance to the library.
Mayor Hildenbrand is mentioned only in Fallout 4.