John T. Doyle was born in New York City on November 26, 1819, the son of John Doyle and Frances Glinden Doyle. In 1838, he graduated as valedictorian from Georgetown University in Washington, D.C. Obtaining an A.M. in 1840, he began practicing law in New York two years later and continued until 1851. Then, on a vacation in Nicaragua, he met "Commodore" Cornelius Vanderbilt, the shipping and railroad magnate, who was trying to fulfill his dream of a canal linking the Gulf of Mexico with the Pacific Ocean. Inspired by the tycoon's vision, Doyle rushed back to New York, resigned his position, and returned to Nicaragua as general agent for Vanderbilt's American Atlantic and Pacific Ship Canal Company. He spent a year making plans, none of which came to fruition because the "Commodore" could not raise the money needed for construction costs. Doyle finally gave up and headed for San Francisco. In 1853, he was admitted to the San Francisco bar, where he remained until 1888 as an active attorney. It was not until 1889 that he received his L.L.D.

Doyle sought no public office, though he was appointed to two during his career. In 1868, he became one of the first members of the board of regents of the University of California. A few years later, Governor Irwin made him a member of the Board of Commissioners of Transportation. This was more to his liking, for he felt keenly the general resentment of the discriminatory and onerous rates that the railroads charged. He became a crusader for thorough reform in railroad legislation. The Commissioners agreed with his recommendations, but the corporations were less tractable. As he later recalled, "The railroads scented the danger afar, and rallied their lobby to the defense of their prerogative of plunder." The House amended a reform bill so that it legislated the Commissioners out of their jobs. A single Commissioner replaced them, but he too was superseded when the Constitution of 1879 created a Board of Railroad Commissioners. This change did not please Doyle; he claimed that the state was so apportioned that two of the three members of the board would remain under company control.

It was, however, as a legal advocate that Doyle was famed. He went through a succession of partnerships: Janes, Doyle, Barber & Boyd; Doyle & Barber; Doyle, Barber & Scripture; Doyle, Galpin, Barber & Scripture; Doyle, Galpin & Scripture; Doyle, Galpin & Ziegler; and after his retirement around 1890 (sources disagree as to the exact date) set up a practice on his own. It was then that he won his greatest victory. In 1876, he had recovered from the Mexican government a judgment of $904,000 for interest and capital held by Mexico for the Catholic Church in California. The case dragged on until 1902, when Doyle pleaded it before the International Tribunal in the Hague -- the first case argued before it. The Court awarded the Church $1,426,000 which included accruing interest. It decreed that henceforth Mexico must pay the church $43,000 a year forever.

In May, 1863, Doyle married Miss Antonia Pons, the daughter of a silk manufacturer in Lyons, France. They had eight children: five sons and three daughters. Doyle himself was able to read Latin, French, Spanish and Italian -- an advantage in his profession -- and in his spare time wrote a treatise explaining how consistent was the trial in Shakespeare's Merchant of Venice with legal customs of the time. He was a founder of the Ethno-Historical Society in 1866, a precursor of California Historical Society and he served two terms as first president of the latter, in 1887 and 1888.

At home "among his books and vines and fruit trees" in Menlo Park, a contemporary account commented, he spent a happy old age. "Though impatient and irascible," it added, "he is good-natured at heart, and has materially aided many young members of the profession, who have been indebted to him for encouragement, opportunity and guidance."

Doyle died at age 86 in 1906.