Greenhalge served in the office from January 1894, winning reelection until his death in 1896. While governor, the Commonwealth paid off its last public debt and he proclaimed the first Patriots' Day, ending the 200-year-old Fast Day celebration in Massachusetts. Perhaps his greatest test in office came in February 1894 when an angry mob of 5,000 gathered in front of the State House to demand unemployment subsidies; he came out of his office to address them and promise them relief, whereupon their anger subsided.