John T. Murphy was born on a farm in Platte County, Missouri, on February 2, 1842, the first of two children of William S. and Amelia Tyler Murphy. John helped his father on the farm and attended a private school until the age of 17 when he set out on his own. Murphy joined the Colorado gold rush, but as a merchant, not a miner. For the first year and a half, he was a clerk in a Denver store. He then moved to Nevada City, Colorado, where he opened his own store. With profits from this operation and with experience gained from a brief employment with Ben Holliday's Express, Murphy bought several teams and wagons, and returned east for goods. He made several trips to Colorado

In 1864 brought a wagon train of supplies to the new Montana Territory mining town of Virginia City. He did so well financially with this first trip that the following spring he brought another wagon train to Montana, this time to Helena by way of steamer to Fort Benton. With these goods, he took on two partners and established the firm of Tutt, Murphy and Neel. This mercantile house, under the later name of Murphy, Neel and Company, established branch stores at Fort Benton and Deer Lodge. Like most of the successful mercantile men of the period, Murphy diversified his holdings. He expanded his interests into mining, banking, stockraising, and Florida citrus crops. It was in stockraising, however, that Murphy had his most marked success. His Montana Cattle Company, with its famous "79" brand, established the Seventynine Ranch in the area between the Yellowstone and Musselshell rivers south of Ryegate. Initially established as an open range operation, the "79" was one of the few to successfully make the transition to fenced ranching. Like many Montana ranchers, Murphy was able to effectively combine cattle and sheep ranching. In the field of banking, Murphy was one of the organizers of the Helena National Bank in 1890 and the Montana Savings Bank the next year. Following the death of C.A. Broadwater, Murphy was chosen president of the Montana National Bank in Helena. Murphy also had mining interests in Lewis and Clark and Jefferson counties, among them the Poorman, the Jay Gould, the Rumley, and the Silver Bell mines.

John T. Murphy married Elizabeth T. Morton in 1871. They had four children: William M., Frances D., Adelize M., and John T., Jr., all born in Helena in the 1870s. Murphy's wife died in 1897, and his son William in 1904. A few years after the death of his first wife, Murphy married Clara Cobb of Providence, Rhode Island. John T. Murphy died May 23, 1914, in Helena.