Harrigan made his first stage appearance in 1867 at the Olympic, Their breakthrough hit was the 1873 song and sketch "The Mulligan Guard", a lampoon of an Irish neighborhood "militia" with music by
David Braham, who would become Harrigan's musical director and father in law. It became their signature piece, and they featured it in many of their slapstick skits and plays. In 1876, Harrigan took over the Comique himself, along with Hart and manager Martin Hanley. By 1878, with
The Mulligan Guard Picnic, Harrigan & Hart settled down on Broadway and performed in seventeen of their shows over the next seven years. Though still broad and farcical, these shows featured music that was integrated with a more literary story line, together with the dialogue and dance, and the shows began to resemble modern
musical comedy. Harrigan wrote the stories and lyrics, and Braham wrote the music. Although the plays gradually became longer as more songs, dances, and stage business was added, the tickets remained the same price. Harrigan and Hart's comedy was about everyday people, and so it was fitting that working folk were able to afford to fill up the seats. These shows were very popular, especially with New York's immigrant-based lower and middle classes, who were delighted to see themselves comically (but sympathetically) depicted on stage. The action of the plays took place in downtown Manhattan and concerned real-life problems, such as interracial tensions, political corruption, and gang violence, all mixed with broad, street-smart comedy, puns and ethnic dialects. Harrigan played the politically ambitious Irish saloon owner "Dan Mulligan", and Hart played the
African-American washerwoman "Rebecca Allup". One of Harrigan's most popular plays with the Mulligan Guard Series, the ''Mulligan Guard's Ball'' (1880), shows off the smooth juxtaposition of the comedy, musicality, and a healthy dose of humanity that made Harrigan's plays so distinctive. Full of laughable chaos and "Harrigan hilarity", the Irish militia and Black militia within the act butt heads in a satirical whirlwind of dance, stage violence, and buffoonery. The
New York Herald compared the Mulligan series to the
Pickwick Papers by
Charles Dickens, and one devotee wrote: "America has produced nothing more national, more distinctly its own, than these plays of the Irish in New York". Although the Theatre Comique was eventually shut down for financial reasons, Harrigan announced in 1881 that they would build a fresh and elegant "
New Theatre Comique" several blocks further north on Broadway. The building they renovated was originally the home of the Church of the Messiah but had hosted many other theatres throughout the years. However, this theatre was not to last; it burned to the ground in 1884. ==Marriage and decline==