[1][3] In 1840, he and his new wife crossed the Great Plains on what became the Oregon Trail with P. B. Littlejohn and the Reverend Harvey L. Clark and their wives, along with fur traders.

[4] They left in March after Smith had heard a speech about a group of Native Americans who had traveled to St. Louis, Missouri, and asked to learn about Christianity.

[5] There he built a log cabin on his 643 acres (260 ha) farm and later donated to Tabitha Moffatt Brown's orphan school in 1845 that grew to become Tualatin Academy and then Pacific University.

[9] In 1856, he completed building a new two-story frame home, which was added to the National Register of Historic Places on November 8, 1974, as the Alvin T. Smith House.

[7][10] On April 17, 1858, his wife Abigail died, and later that year Smith assisted in building the Forest Grove Congregational Meeting House in September.

[7] Alvin Thompson Smith died on January 22, 1888, in Forest Grove at the age of 85 and was buried at Mountain View Memorial Gardens in that city.