Hayne began her early career as a teacher, working at schools in Lonsdale, Rhode Island, as well as Leicester and Lowell, Massachusetts.

In 1872, after retiring from the library, she entered St. Lawrence University, Canton, New York, and before completing the course there, was called to the pastorate of the Universalist Church in Hallowell, Maine.

While occupying this place, she officiated as chaplain in the House of Representatives and also in the Senate, in Augusta, Maine; this was the first instance of a woman acting in that capacity in that State.

[3] Haynes, Phebe Ann Coffin Hanaford, Mary H. Graves were the first Massachusetts women to become ordained Christian ministers.

[6] The next year, he bought from Cato, a Native American, for the sum of five pounds, a tract of land, now the town of Sudbury, Massachusetts.

[7] From childhood, Haynes showed an unusual interest in books, and, raised in a town which had a library and an annual course of lectures, she became a constant reader and student.

She taught one of the public schools in her native town for nearly two years, but her love for studying was so strong that she went for a time to the academy in Leicester, Massachusetts.

[7] After her time at the Leicester academy, she taught at a public school for six years in the city of Lowell, Massachusetts and there made the acquaintance of Margaret Foley, a cameo cutter.

[9] After six-and-a-half years of service, she resigned her office in order to enter the Universalist Theological school of St. Lawrence University, Canton, New York.

Olympia Brown, who wished her at once to take charge of a parish which was open to her; however, Haynes was not willing to take the work as she was less equipped theologically than young men graduates.

Having previously bought a home in Waltham, close to the family homestead, where her only surviving sister resided, she went to live there permanently in July, 1889.