Born and raised in Paterson, New Jersey, Hobart was the daughter of the prominent attorney Socrates Tuttle and his wife, Jane Winters. She married Garret Hobart in Paterson on July 21, 1869, at the start of his career as a lawyer and politician. They had four children, two of whom died in childhood. The other two were Garret Jr. and Fannie, who died in 1895. In 1896 her husband was elected Vice President of the United States and the family moved to Washington, D.C.. As Second Lady of the United States, Hobart often served as White House hostess because the First Lady, Ida Saxton McKinley, suffered from epilepsy. Vice President Hobart died of heart failure on November 21, 1899. After his death, she returned to Paterson and became involved in community affairs. She was a close friend of Mrs. McKinley and rushed to Buffalo, New York, to offer her support when President McKinley was shot in September 1901.