Hazelbaker married Carrie Eveline Woodworth (1887-1919), daughter of rancher and state legislator George E. Woodworth, in 1905; their son Frank W. Hazelbaker (1912-1990) also served in the state legislature. After Carrie's death of pneumonia during the Spanish flu pandemic, Hazelbaker married Lois Brown Brantly (1894-1972), the daughter of Theodore M. Brantley, the Chief Justice of the Montana Supreme Court; they had one son, Theodore Brantley Hazelbaker (1930-2006), who served several terms as chairman of the Montana state board of education.
