During that time, Martha Clark would serve as his private secretary, and spent a year in Utah with Obediah Strickland, a federal judge.

Objecting to marriage as an institution "founded on the principle of master and slave," Clark refused to marry, but entered into a domestic partnership contract with Leo Miller in 1875.

On October 9, 1888, she became the first woman to argue a case in front of the Michigan Supreme Court, Thompson v. Thomson, winning a divorce for an abused wife.

The second case she argued was Wilson v. Newton, concerning the right of women to hold the office of deputy county clerk, was decided in her favor.

Little is known about her subsequent life, but Clark continued to lecture into the 1930s, and was honored by the American Bar Association in 1933, shortly before her death on June 17, 1935.