February 20, 1834, Alfred, New York.
February 20, 1917, Milton, Wisconsin.
Oak Grove Cemetery, Hopkinton, Rhode Island.
Jairus was the son of Maxson Stillman and Lydia C. Chapman, and husband of Clara Lenore Langworthy.
As a young man, he learned the trades of millwright and carpenter from his father. His heart was set on music, though. In the summer of 1857 he studied at the Normal Musical Institute at North Reading, Massachusetts, under Lowell Mason, George Root, and others. At the same time, he studied Voice Culture under Auguste Kreissman of Boston. During the summers of 1859 and 1860, he attended the Normal Musical Institute at Genesee, New York, taking pianoforte lessons from T. J. Cook, and lessons in Voice Culture from Carlo Bassini, both of New York. From 1861–62 he studied pianoforte at Milton College, reciting also in the German classes. In the summer of 1870 he attended the National Normal Music Institute at South Bend, Indiana, again taking private lessons under Bassini. From 1870–1874 he was a pupil of Dudley Buck of Chicago and Boston, in harmony and counterpoint, taking his lesson partly by mail and partly in person.
In the winters from 1858–61 Stillman taught singing schools and gave private lessons in Shelby and Logan counties, Ohio, and led the Lutheran Church choir at Bellefontaine, and the Seventh-day Baptist choir at Jackson Center. In 1862, 1864 and 1866 he was professor of vocal and instrumental music at the Hopkinton Academy, Ashaway, Rhode Island; in the winter months he taught singing schools six evenings each week, and at the same time taught as many as thirty private students. During the years 1863, 1865 and 1867 he directed the music department at Alfred University, his classes embracing Pianoforte Music, Voice Culture, and Elementary and Chorus Singing. Later in his career, Stillman conducted singing schools in many states, and became a professor of music at Milton College, Wisconsin.