Golden trout occupy only high-altitude freshwater lakes and streams in scenic mountain areas. These altitudes can range anywhere from about 9,000 to 12,000 feet (2.7 to 3.7 kilometers). The water the fish dwell in is usually very cold contain little weed growth.

The Little Kern golden trout occupies a small number of headwater streams in the Little Kern River Basin in the Sierra Nevada range, Tulare County, California. The Little Kern is a tributary of the Kern River. The elevation of the Little Kern is about 6,000 to 10,000 feet (1.8 to 3 kilometers). is the subspecies occurs within the Sequoia National Forest and Sequoia National Park.

Transplants drastically altered the range of this species. Early anglers made "coffee pot" transfers that established it in waters outside its historic range. Later transplants of non-native trout into the Little Kern River basin displaced the species from many of its historic habitats. Recovery efforts by the California Department of Fish and Wildlife, U.S. Forest Service and National Park Service have restored Little Kern golden trout to parts of its historic range.

The Little Kern golden trout is a member of the Salmonidae family of trout and salmon. It is a brightly colored fish with profuse spots on the back and tail. The belly and cheeks are red to red-orange. The lower sides are bright gold. The lateral band is red-orange. The back is olive green. Pectoral, pelvic and anal fins are orange, with white tips. Little Kerns typically retain up to 10 parr marks, or vertical dark oval spots, on each side as adults. They average about 5 to 7 inches (13 to 18 centimeters) in length.

The Little Kern subspecies is distinguishable from the California golden trout (Oncorhynchus mykiss aguabonita) and Kern River rainbow trout (Oncorhynchus mykiss gilberti) primarily by coloration, spotting characteristics and parr marks. Unlike the California golden trout, the Little Kern typically has many spots on the head and below the lateral line. The parr marks are arranged vertically on both sides of the body with an intermediate row of smaller ones often occurring just below the main row.

Little Kern golden trout spawn just after snowmelt in late May or early June. Females contain between 41 and 65 eggs per year and develop new eggs soon after spawning for next season. The eggs hatch after about 26 days in water between 54 and 61 degrees Fahrenheit (12 and 16 degrees Celsius). Spawning gravel has been found to be between 0.2 and 0.4 inches (5 and 10 millimeters) diameter in water between 2 and 6 inches (5 and 15 centimeters) deep.

Estimated life span is six to seven years based on the life span of the closely related California golden trout.

The diet of the golden trout consists mainly of surface water-dwelling insects, principally small ones such as caddisflies and midges. They also eat small crustaceans, including tiny freshwater shrimp.