In 1840, Smith wrote the manuscript for the book Grammar of the Language of the Nez Perces Indians Formerly of Oregon, U.S..

[8] He transferred to Middlebury College, a Congregational-supported school, in 1832 and he graduated with a Bachelor of Arts degree in 1834.

[11] In the spring of 1837, he preached at the Congregationalist Church in Woodbridge, Connecticut, five miles northwest of New Haven.

[1][2] Her parents, Sarah Gilbert and Alfred White of West Brookfield, Massachusetts,[15] had been missionaries.

[1][2] Sarah kept a diary of her experiences from March 10, 1838, through September 14, 1839,[21] which narrated the Smith's journey from Springfield, Massachusetts, to the Whitman Mission in Waiilatpu in present-day Washington.

[25][26][d] Mary Sabin Locke was adopted by her uncle Dr. Samuel Newell Bowell of Malta, New York.

[28] She married a man named Wilson, lived in San Francisco, and had a son who was a missionary in Hawaii.

[1] On March 15, 1838, the same day that they were married, the Smiths traveled across the American continent towards the Pacific Ocean.

[34] The missionaries had a difficult time establishing themselves with the local Native Americans, due to language barriers and vast differences in religious concepts.

[1][2][f] Smith felt that the natives should not acquire the white people's way of life, concerned that they would become "worldly minded".

[37] In the Smith's letters and diaries, they wrote in great detail about the lives of the Nez Perce people.

This provided a "wealth of new information not only upon the customs, traditions, and manner of life of the Nez Perces, but also upon the difficulties which the pioneer missionaries faced in their isolated stations.

"[38] Sarah's mental and physical health were very poor and Smith took care of the farm and the housekeeping.

[36][g] About early May 1839, the Smiths went to Kamiah, south of Lapwai in present-day Idaho, which was the heart of Nez Perce country.

Initially he was there to learn the Nez Perce language, but after some time, a new mission station was opened at Kamiah.

Lawyer knew two native languages, that of his father Chief Twisted Hair and his mother a Flathead woman—as well as some English.

[44] Smith developed a Nez Perce grammar by adapting the missionary alphabet used in Hawaiian missions.

[2] In 1840, Smith wrote the manuscript for the book Grammar of the Language of the Nez Perces Indians Formerly of Oregon, U.S..

[45] Insinmalakin and Inmtamlaiakin, subchiefs of the Nez Perce at Kamiah, ordered Smith to leave the village on October 14, 1840.

Needing a better climate, they went to the Sandwich Islands, arriving on January 25, 1842, where the couple's health improved significantly.

[29] At his request, Smith was transferred to the Sandwich Islands (Hawaiian) Mission in 1842[1][2] and stayed there until October 1845.

[22] Smith's voice failed in 1845 and they left the islands, traveling a seven-month journey to Canton, China and around Cape Horn, and then to Massachusetts.

[25] Harriet had poor health that prevented the Smiths from going to Minnesota for the American Home Missionary Society.

[49] Papers regarding his position with the American Board of Commissioners for Foreign Missions are among the collection of the Research Library of the Oregon Historical Society.