[1] Fifield studied law at the Montpelier firm of Lucius B. Peck and Stoddard B. Colby, and was admitted to the bar in 1858.

[3] Beginning in 1869, he served as counsel for the Central Vermont Railway, and his effective representation of corporations became so well known that he acquired clients from throughout the northeastern United States.

[1] When U.S. District Judge David Allen Smalley died in 1877, Fifield was the leading candidate to replace him, but withdrew in order to continue representing the Central Vermont Railway and other clients in pending litigation, which he did in addition to his U.S. Attorney's duties.

[2] In 1893, Fifield was one of Vermont's commissioners for creating and operating the state's exhibits at the World's Columbian Exposition.

[2] In the mid-1890s, Fifield retired from most legal business, but continued to serve as counsel for the Central Vermont Railway.

[2] Fifield initially gave his tentative acceptance, but declined several days later, informing Smith that he felt obligated to turn down the appointment so he could care for his wife during her final illness.