After his father died, William Welles Hollister, with his eyesight failing, left college without graduating, and went to farming and merchandising.

The party took a southern route from Salt Lake City in order to avoid the winter snows of the Sierra Nevada.

Although only about a thousand sheep survived, Hollister was able to make a considerable fortune when wool prices spiked during the Civil War, as well as catering to those who searched for gold.

Rancho San Justo was held jointly by the Flint, Bixby & Company and Hollister until 1861, when they disagreed over a business matter and dissolved their partnership.

He remained at Rancho San Justo for 14 years before selling the 20,773-acre (84.07 km2) South Valley ranch for $370,000 and moved south with his family to raise sheep in the Santa Barbara region of California, settling on the eastern portion of the former Mexican land grant Rancho Dos Pueblos, purchased from the estate of Nicolas A. Den in 1862 and renamed Glen Annie Ranch after his wife.

The main street of Goleta, California, once part of Glen Annie Ranch, is named Hollister Avenue.