Hackett was born in
Albany on December 7, 1868, the son of John Hackett and Martha Stormont. His family resided in Albany's
South End neighborhood, and Hackett was educated in Albany. He began working while still a boy, including delivering the
Albany Evening Journal newspaper, which was later owned by Republican Party leader
William Barnes Jr. After two years at
Albany High School, Hackett dropped out in order to begin
studying law in the office of Albany attorneys
Amasa J. Parker Jr. and Edwin Countryman. He was
admitted to the bar in 1889, and then practiced law in Albany. Hackett also joined the
New York National Guard, serving in Albany's Company A, 10th Battalion (formerly the Albany Zouave Cadets). He was a member of the unit from 1890 to 1899, and attained the rank of
sergeant. Hackett later served as treasurer and president of Company A's veterans association. A lifelong bachelor, Hackett was a member of the
Baptist church, and became a
lay preacher. He was also active in the
Freemasons, and served as Master of Albany's
Masters' Lodge Number 5 from 1900 to 1902. He was Master of the Albany chapter of Rose Croix, and Commander in Chief of the Albany consistory of the
Scottish Rite Masons. Hackett was a member of
the Elks, the Fort Orange Club, the Albany Club, the Albany Country Club, and the Wolfert's Roost Country Club. ==Business career==