The original lighthouse at South Hyannis (or Hyannis Harbor) was a shack with a lamp and reflector borrowed from Point Gammon. Given that Hyannis harbor was a busy harbor in the 19th century, the government established a lighthouse - a small, white tower - at the harbor entrance in 1849. A keeper's house was constructed in 1850. A Fresnel lens was installed in 1856.

A lighthouse keeper position was a political appointment. This is apparent from the list of keepers at South Hyannis. The first keeper, Daniel Snow Hallett, was replaced in 1849 (when Millard Fillmore was elected) by James Bearse. When Franklin Pierce was elected, Bearse was replaced by Daniel Hallett's brother Almoran.

The wharf at Hyannis was a very busy place in the late 1800's. There were moorings for a dozen ships, a daily steamer from Nantucket, and several businesses. Keeper John Peak would often have to ask the railroad nearby to move freight cars parked near the beacon, which blocked the short light!

In 1885 a lamp set atop a 20-foot tower was installed at the end of the wharf, to serve as a range light. The tower was rebuilt in 1886 due to problems of the range light blowing out during storms. The main light had a summer kitchen and oil house added in 1889.

The lighthouse was decommissioned in 1929, and sold to private ownership. The lantern room was removed. The tower at the end of the wharf received a 230 candlepower acetylene beacon. The lighthouse was sold to private owners, who built an enlarged lantern room atop the tower for use as a sitting room.

References (see links)

Lighthouses of Cape Cod, Martha's Vineyard, Nantucket - Their History and Lore, Clark pp. 105-110
The Lighthouses of New England, Snow p. 323
Massachusetts Lighthouses - A Pictorial Guide, Thompson p. 60
Lighthouses and Life Saving Stations Along the Massachusetts Coast, Claflin pp. 82-83
Lighthouses of Massachusetts, Roberts and Jones p. 61