Michael James Riordan was born in Chicago in 1865 to Timothy Riordan and his second wife Mary White (1820-1883). In 1869, while Dennis was fighting the Civil War, the family bought a farm in Saint Charles, Illinois. During the four years he lived on the farm, Michael learned valuable skills he would have missed had he stayed in the city, just as Dennis had learned skills in the Army. After selling the farm the family moved back to Chicago and Michael was educated at Catholic Parochial schools. At 17 he began studying poetry and rhetoric at St. Ingnatius College. Deeply religious, he was received into the Jesuit Novitiate at Florissant, Missouri in 1883. Unfortunately, his health soon gave out, interrupting his education. His doctors told him his tubercular illness would affect him less severely in the west, and he followed their advice. He moved to a Jesuit house in Albuquerque in early spring 1885 but did not find much relief. At his brother Dennis’s insistence he moved to Flagstaff in May. In the dry mountain air, his condition immediately improved.

Michael fell in love with Flagstaff and northern Arizona, he often wrote articles on the landscape and his experiences for Chicago newspapers. His most famous article described the time he accompanied noted explorer John Wesley Powell during trips to excavate prehistoric ruins in Walnut Canyon just east of Flagstaff. Despite all this, he still desired to return to his involvement in religion, and in 1886 he returned to New Mexico to accept a position at Las Vegas College, a Jesuit Parochial School. Once again his health got in the way, and in just a few weeks he was forced to return to Flagstaff. He started working in the office of the Ayer Lumber Mill in November of 1886, and by March 1887 he became manager of a company commissary in Williams. When his brother Dennis bought the company, Michael was made secretary, the position he would hold for the rest of his life.

Around this time Michael Riordan met Elizabeth Metz. Elizabeth was one of three sisters who paid long visits to Flagstaff to visit their first cousins, the Babbit brothers. The women were daughters of a successful Cincinnati tobacco grower and cigar manufacturer. For Michael and Elizabeth almost immediately love, as Michael wrote in 1888:

The love which she sent is to my soul, pinning away here in the desert, even as the fragrant breath of morning is to the unblown rose, or let me make it yet stronger; even as the full bottle is to the laddie who loves his last drop.

They were married in Cincinnati at Holy Trinity Church in 1892. They would go on to have six children: Victor, Blanche, Arthur, Clare, Robert and Richard. Like Dennis, Michael was strongly involved in the community. Together with other Catholics, Michael founded Church of the Nativity, which held its first mass on Christmas night 1888. The Church of the Nativity still serves Flagstaff today. Just one year later in 1889 Michael established the committee for Flagstaff’s first library. It opened in 1890 with Michael Riordan as President and George Babbit as Vice President. In 1901 Michael was elected on the Republican ticket to the 21st Territorial Legislature in Phoenix. He died in 1930 at 65.