Businessman, secretary of the Longmont, Colorado, Commercial Association, 1890s-1920s, and chairman of Colorado Catholic Charities and the Mexican Welfare Committee, Colorado State Council, Knights of Columbus, 1920s-1930s. An advocate for Colorado's Mexican-American migrant sugar-beet laborers.

Thomas F. Mahony was born in 1873 on his family's farm in Meadville, PA. While Mahony was still young the family moved to Ashtabula, Ohio where Mahony grew up, the eldest of seven children in a devout Irish Catholic household. The senior Mahony was a butcher, and the family was not wealthy. Mahony had only five to six years of formal education, but as a child and young man he read voraciously.

In 1901, Mahony began a long association with Equitable Life Assurance Society. The following year he headed west to persue insurance opportunities. Moving through Denver, Mahony settled in Longmount, Colorado a small town fifty miles north of Denver.

In 1908, Mahony married a Longmount native and soon had three children. He spent some time working in Grand Junction, CO., as Secretary to the Chamber of Commerce, and also spent several years in real estate in Montana and working for the Chicago Tribune Land Show, a job that required him to travel around the country.

In the early 1930's, Mahony began his work as an advocate for migrant Mexican Sugar Beet workers. He became Chairman of the Colorado Knights of Columbus Mexican Welfare Committee. Relying on the Papal Encylicals and the work of Father John Ryan for guidance, Mahony pressed for better working and living conditions in the sugar beet fields. In this endeavor, Mahony also served as Chairman of Colorado Catholic Charities, and worked with the Child Welfare Committe of the League of Nations and the International Conference for the Protection of Migrants.

Beginning in the late 1930's, Mahony turned some of his attention toward combating the spred of communism, the appeal of which he feared would negatively affect the migrant works he hoped to help.

Surviving several illnesses and continuing to work into his later years, Mahony died in 1957 at the age of 83. Parts of Mahony's life and works were chronicled by his daughter, Sister Marineil Mahony, SL in her Master's thesis, prepared at the University of Notre Dame, entitled Some Approaches to the Problems of the Mexican Migratory Beet Laborer in Colorado (1923-1933) by the Knights of Columbus Colorado Mexican Welfare Committee Under the Chairmanship of Thomas F. Mahony, Longmount, Colorado.