Congress appropriated $3,000 for the building of a lighthouse on the island in July 1838.The first lighthouse building took the form of a wooden tower on the southern end of the roof of a small rubblestone dwelling; its seven lamps and 13-inch reflectors in an octagonal wrought-iron lantern showed a fixed white light 98 feet above mean high water. A 10-foot-wide embankment of logs and gravel was formed to the west of the lighthouse for protection. A fire did great damage to the lighthouse building in 1852, and the 1854 annual report of the lighthouse board announced that the station had been rebuilt. The new lighthouse consisted of a round brick tower at one end of the dwelling. It seems likely that much of the original dwelling was salvaged during the 1853 rebuilding.
A fifth-order Fresnel lens was installed in 1856. In 1888, a 1,000-pound fog bell and striking apparatus were installed. Also in 1888, the dwelling was reported to be quite dilapidated.The present 31-foot brick lighthouse was built in 1889–90 after a congressional appropriation of $3,750, as were a new one-and-one-half-story, wood-frame keeper’s house and a barn. An oil house and boathouse were added later. The Fresnel lens was moved to the new tower, exhibiting its light from 100 feet above the water. Bear Island remained a family light station under the U.S. Coast Guard. In the late 1950s, Terry and Nancy Stanley lived at the lighthouse. In the early 1980s, Bear Island Light was discontinued and replaced by an offshore lighted bell buoy. The property became part of Acadia National Park in 1987. Through most of the 1980s, the station fell into disrepair
In 1989, the Friends of Acadia refurbished the keeper's house for $17,000 and the tower was relighted as a private aid to navigation. The National Park Service then granted a long-term lease on the property to Martin Morad, who is required to pay for the upkeep of the property. Morad, originally from Iran, is a professor of pharmacology and medicine at Georgetown University. Fabiola Martens, his wife, is Belgian. She is a former lawyer and now is an interior designer. Morad had originally seen Bear Island Lighthouse in 1971 and had attempted to buy or lease it to no avail. By 1989, the house had fallen into such poor condition that it took three years of renovation before Morad and Martens could move in.
Service was discontinued in 1982 but it was relighted in 1989 as an automatic and private aid to navigation. The lighthouse is on Acadia National Park land but is privately leased and closed to the public.