[2][1] Ephraim Clark and his wife Mary Kittredge were part of the Third Company of missionaries sent to the Kingdom of Hawaii by the American Board of Commissioners for Foreign Missions.

The sea voyage aboard the Parthian began November 3, 1828, and took 148 days, during which the missionary passengers lived in cramped roach-infested quarters, with inadequate eating utensils.

[5] Clark was called to be Kahu (pastor) of Kawaiahaʻo Church in 1848, to succeed Richard Armstrong who had been appointed Minister of Public Instruction.

The church as a body of believers had existed since Hiram Bingham arrived in 1820, and began meetings adjacent to his thatched hut.

[9] Queen Victoria had already consented to be the godmother of four-year-old Crown Prince of the Kingdom of Hawaii Albert Kamehameha, in a ceremony conducted by an Episcopalian bishop.

Even though Clark was a Congregational minister, the child's parents Kamehameha IV and Queen Emma arranged for him to perform the Episcopalian ceremony.

The service was held on August 23, with the newly arrived British commissioner William Webb Follett Synge and his wife as stand-ins for Queen Victoria.

[10] When he resigned as Kahu of Kawaiahaʻo Church in 1868, Clark was president of the committee to revise the Hawaiian language translation of the Bible.

[11] He had been involved with the original translation project for decades, and had made trips to the mainland United States in 1856, 1859 and 1864 to meet with printers.

Over the years, the project came to include the Royal Governor of Hawaii Kuakini and Hawaiian scholars Samuel Kamakau, John Papa ʻĪʻī and David Malo.

[13][11] Other translations Clark was involved with include "First Lessons in Astronomy", text-books on geometry, trigonometry, and surveying, and the children's book The Little Philosopher.