After receiving an education in mission schools, he returned to Maryland to study theology.

Ordained a priest, he served as rector of the Episcopalian Trinity Church in Monrovia.

With the election of William D. Coleman as president in 1896, Gibson was appointed secretary of the interior.

In 1903, the British forced a concession of Liberian territory to Sierra Leone, but tension along that border remained high.

Whenever the British and French seemed intent on enlarging at Liberia's expense the neighboring territories they already controlled, periodic appearances by U.S. warships helped discourage encroachment, even though successive American administrations rejected appeals from Monrovia for more forceful support.