A native of Jersey City, New Jersey, William Gilbert Gaul became largely identified with the South and portrayals of the Civil War. He attended school in Newark and at the Claverack Military Academy. Poor health barred him from military service, and he moved to New York where he studied art with Lemuel E. Wilmarth at the school of the National Academy of Design from 1872 to 1876, and privately with the noted genre painter, J. G. Brown. He continued his training at the Art Students League during 1875 and 1876. Gaul first exhibited his work at the National Academy in 1877.

In 1881, he inherited a farm in Van Buren County, Tennessee, from his mother’s family. He lived on the farm for four years to fulfill the terms of the bequest. During this period, he painted pastoral landscapes, rural genre scenes, and remembrances of the recent American conflict. His war paintings are characterized by a dramatic appeal and strong academic technique while his genre scenes often hinge on a poignant or sentimental depiction of a single figure.

Gaul became highly regarded as an illustrator, garnering recognition for his contributions to Harper’s Monthly; Century Magazine, Scribner’s Monthly, and Cosmopolitan. In 1885, he returned to New York though he also continued to spend time at the farm in Tennessee. He became a regular exhibitor at the National Academy annuals between 1877 and 1902; in 1882, he was accorded the status of full academician—the youngest artist to attain the honor. He exhibited at the 1889 Paris Exposition; the 1893 World Columbian Exposition in Chicago; and the 1902 Pan-American Exposition in Buffalo, where he was awarded medals.

An inveterate traveler, in 1876 Gaul made his first trip to the American West, an area for which he developed a particular affinity. He made numerous western trips in subsequent years, photographing and rendering scenes of Native Americans and the frontier, which he would later work up into paintings in his studios in New York or Tennessee. In 1890, he worked for the United States census on reservations in North Dakota. He also visited Mexico, the West Indies, Panama, and Nicaragua. An account of his travels was published in Century Magazine in 1892.

In 1904, he returned to Tennessee and settled in Nashville. The decreasing interest in Civil War subjects resulted in financial hardship for Gaul. He gave private art lessons, and taught at the Watkins Institute, Nashville, and at Cumberland Female College, in McMinnville. He also spent time in Charleston, South Carolina, and was living with his stepdaughter while taken ill. By 1910, he had moved to Ridgefield, New Jersey, where he continued to paint and live out his remaining years.

Gilbert Gaul's works can be found in permanent collections of many of the nation’s museums, including the Corcoran Gallery, High Museum of Art, New-York Historical Society, and National Portrait Gallery.