Sockeye salmon typically spawn in streams that flow into large lakes systems to allow juvenile sockeye to rear for a year or more in a deepwater lake environment before migrating to sea. Prior to the 1930s, Lake Washington was famous for its large populations of kokanee (the freshwater form of the sockeye), but sea-run sockeye salmon were thought to be absent. In the year 1916, the ship canal was opened to serve as a new outlet for Lake Washington and to provide the water needed to operate the just completed Hiram M. Chittenden Locks at Ballard. This combined the extensive spawning grounds of the Cedar River with a large lake rearing environment, provided an opportunity to develop a major sockeye salmon population in the waters of southern Puget Sound.

Sockeye were introduced into the Lake Washington watershed in 1935 (and subsequent years) from the Baker River. The first documented adult returns to Lake Washington were in 1940 when 9,099 sockeye were counted at the Washington Department of Fisheries hatchery on Issaquah Creek. The run gradually increased, and in 1970 an escapement goal of 350,000 spawners was adopted and in 1971 the first directed fisheries occurred. Since then, sockeye returns have significantly fluctuated (see figure below) despite supplementation efforts and harvest restrictions, theoretically due to freshwater and ocean survival constraints, and because of an increased frequency in damaging winter floods.

Genetic studies of the Cedar River and Issaquah Creek sockeye show that the present run is genetically similar to the Baker sockeye stock. Recent genetic studies of northern Lake Washington tributary sockeye and beach spawning sockeye have revealed that these groups of sockeye is also related to the introduced Baker stock, suggesting that all current sockeye populations in the system are derived from the introduced fish.