After the war, Sparks drove cattle in the huge Longhorn drives of the era, at first working for John Meyers, and later in partnership with his brothers.

In 1873, Sparks bought a large herd of cattle in Texas then drove them to Wyoming and established a ranch in the Chugwater River valley near Cheyenne.

In 1879 his wife died, and in 1880 Sparks married her half-sister Nancy Elnora "Nora" Knight, they had three sons, Benton, Charles and Leland.

Joining with fellow Texan John Tinnin, Sparks bought the H-D Ranch in the Thousand Springs Valley north of Elko, Nevada, in 1881.

At that time, the Harrell ranches consisted of approximately 30,000 head of cattle ranging over a vast area of Nevada and Idaho.

In 1885, Sparks moved to his 1,640 acre (6.64 km2) Alamo Ranch, located in the Steamboat Springs area just south of Reno, Nevada.

Sparks became famous at western livestock auctions by paying ridiculous sums for pedigreed Hereford cattle.

Sparks' sale of lesser cattle from his herd helped establish the Hereford as the dominant breed in Nevada.

The survival rate of these Hereford/Longhorn crosses was ascribed to the superior qualities of the Hereford, however hybrid vigor may have played a role.

Between his expenditures on the Alamo Ranch and losses in mining speculation, Sparks also ran into financial trouble and sold his half of Sparks-Harrell back to Jasper Harrell in 1901.