His father was Peter Johnson Gulick (1796–1877) and mother was Fanny Hinckley Thomas (1798–1883), of the American Board of Commissioners for Foreign Missions.

He lived with an aunt and uncle in New Jersey, and then stayed with Luther Halsey (1794–1880, for whom he was named), a classmate of his father's at Princeton University who was now a professor at the Auburn Theological Seminary.

[3] Louisa founded a female school in her home called the Kawaiahaʻo Seminary for Girls,[4] which later became part of the Mid-Pacific Institute.

Another younger brother Orramel Gulick became active in politics, opposing the 1864 Constitution of the Kingdom of Hawaii which only allowed property holders to vote.

He convinced Hawaiian historians such as Samuel Kamakau and John Papa ʻĪʻī to write articles on the culture that was disappearing under a government program to make the English language exclusive in the schools.

He attacked Anglican Bishop Thomas Nettleship Staley and Board of Education member Charles de Varigny (a French Catholic) for aligning the Hawaiian government with old Europe and what he considered unreformed churches.

[1]: 92 Daughter Sarah Frances Gulick (1854–1937) married Professor Frank Fanning Jewett (1844–1926) of Oberlin College on July 30, 1880.

Their son Luther Halsey Gulick Jr. (1865–1918) was a medical doctor who founded Camp Fire Girls and supervised the invention of basketball.