Willis served on the Board of Trustees of
Morristown School (now Morristown-Beard School) for 15 years (1905-1920) and as board president for 12 years (1908-1920). He donated funds to help construct a gymnasium for the school and its Headmaster House (now the school's Alumni House). Willis dedicated the gymnasium fund to his wife Mary Baker Hadock Willis. During
World War I, Willis served with the Morristown Infantry Battalion of the New Jersey Militia Reserve. After a fire severely damaged the Morristown Library and Lyceum, he and Samuel Gillespie funded the conversion of the structure into the Morristown Armory. In 1917, Willis donated $56,000 to fund the construction of a new library for Morristown. He also gave donations to create the building's children's room and a $200,000 fund to meet future needs. ==Family==