A large amount of Lake Harney's history can be accredited to General William Selby Harney and the wars he took part in throughout Florida. Author of “Naming of Lake Harney”, Mal Martin, stated “William Selby Harney was born in Haysboro, Tennessee on August 22, 1800”. When he entered the military, he enlisted as a Second Lieutenant in the First United States Infantry on February 12, 1818 and remained at that rank throughout the first Seminole War which was sparked by Andrew Jackson's attack on a fort held by the Seminole people. After the first Seminole War had subsided Harney was recognized for his military abilities and was raised to the rank of First Lieutenant on January 7, 1819. Harney continued in his military career and, after the end of the Second Seminole war, Harney served in the War with Mexico(1846-1848) and the Civil War until his retirement on August 1, 1863 as a General. After retirement, he married a nurse and lived in Pass Christian, Mississippi for some time. He died on May 9, 1889 in Orlando, Florida and is buried at Arlington National Cemetery. There are several landmarks that are named after him in his honor; such as Harney Peak in South Dakota as well as Camp Harney in Zapata, Texas.
Lake Harney is home to a variety of species of fish and water fowl. It is nominally fresh water with some salt water springs throughout the area. The lake is home to a variety of fish such as largemouth bass, crappie, bluegill, and redear sunfish, all of which are prey to the lake's birds such as bald eagles, ibis, cattle egrets, wild turkeys, a variety of ducks, and various other water fowl. The Lake Harney Wilderness Area is a protected habitat in which the Florida Fish and Wildlife Conservation Commission, or FWC, observes several bald eagle nests in the area.