With no surviving children and an invalid wife, President McKinley's private and family life was narrowly drawn. He usually spent his evenings playing cards with his wife or his personal secretary, George B. Cortelyou, answering letters, and taking walks or carriage rides. He enjoyed smoking cigars—only in private—and occasionally chewed them as well. Just before retiring for the night, he liked to take a drink of whiskey.

He also enjoyed dressing up and meeting people. His trademark pink carnation always decorated his lapel, and he liked giving it to acquaintances as a personal token of his affection. A complete Christian gentleman, he winced at swearing and often prayed before making momentous decisions, including the decision to go to war with Spain. In fact, McKinley opposed going to war in Cuba unless he deemed it necessary to free the island—a stance that Theodore Roosevelt, McKinley's assistant secretary of the Navy at the time, once described as leaving the President with "no more backbone than a chocolate eclair." Although some of McKinley's supporters expressed frustration over his fair-minded approach to life, almost anyone who had spent time with him liked him.