Thomas Jefferson O'Donnell was born on June 2, 1856, in Mendham Township, New Jersey, United States. His father, Michael, and his mother, Amy Winifred O'Connell, the latter a relative of the great Irish liberator, Daniel O'Connell, came to America from Ireland in search of political liberty and economic opportunity. They had ten children.
Thomas O'Donnell was educated in the local public school at Mendham Township, New Jersey, and in William Rankin's Academy.
Soon after Thomas O'Donnell graduated from the academy in 1873, he was made sub-editor of the Morris Republican of Morristown; four years later he founded the Morris County Chronicle. During his journalistic days he acted as correspondent for the Sun and the New York Herald and published a handbook history of Morristown.
From 1876 to 1878 he read law in the offices of Frederick A. De Mott and of George T. Werts of Morristown. In 1879 he moved to Denver, Colorado, and there spent the remainder of his life in the practice of law.
O'Donnell became one of the most noted trial lawyers of the Rocky Mountain region. He was at his best when representing some unfortunate person against whom was arrayed, unjustly in his opinion, the power of the State, or of wealth, or of a hostile press.
Active in politics, O'Donnell was a power in the Democratic party in his adopted state and a delegate to the national conventions of the party of 1892, 1896, and 1904. At the first of these conventions he violently objected to President Cleveland's currency and financial policies, opposed his renomination, and on the adjournment of the convention returned to Colorado to join with other disaffected Democrats in a bolt of the party ticket. He was chairman of the convention of Colorado Democrats in 1892 which indorsed the candidacy of the Populist leaders, James B. Weaver and James G. Field. In the Democratic National Convention of 1896 he represented Colorado on the steering committee of the silver forces which dominated the session. He was several times a candidate for public office but never won an election.
In 1883 he received the Democratic nomination for county judge in Denver; in 1890 he was defeated as a candidate for a seat in the House of Representatives; in 1911 he was one of the unsuccessful contestants for the United States senatorship before a deadlocked state legislature in which ninety-two ballots were taken in a vain attempt to fill a vacancy; and in 1912 he was defeated in the state primary election by John F. Shafroth for the Democratic nomination for United States senator.
Through the midst of acrimonious personal and party contests, he continued to serve the public in various non-partisan capacities: he was a member of Denver's charter convention in 1903; was vice-president and active head of the Colorado commission to the St. Louis Exposition in 1904; a member of the National Conference of Commissioners on Uniform State Laws; and an ardent champion of the Allied and American cause in the World War, in which he took a leading part in relief and patriotic organizations.
Thomas O'Donnell was a member of the Democratic party.
He was one of the organizers of the Denver Bar Association and its president in 1894, president of the Colorado Bar Association in 1916-17, and for many years one of the most active members of the American Bar Association.
O'Donnell also was a member of Denver's charter convention in 1903; vice-president and active head of the Colorado commission to the St. Louis Exposition in 1904; and a member of the National Conference of Commissioners on Uniform State Laws.
Alert, tenacious, independent, and fearless, Thomas O'Donnell always attracted attention in the community by his mental ability and oratorical powers. An uncompromising fighter by nature, and a master of denunciation and invective, O'Donnell naturally made enemies who struck back at him whenever opportunity presented itself in a political campaign.
Thomas O'Donnell was married, on October 24, 1881, to Kathrine Dwyer of St. Louis, who with three of their five children survived him.
