In 1853, Teasdale married Emily Emma Brown, a member of the LDS Church.

In Utah, Teasdale taught school and was a member of the Mormon Tabernacle Choir.

In 1868–69, he returned to England as a missionary to help British Latter-day Saints migrate to Utah.

As an apostle, Teasdale served another mission for the church from 1887 to 1890 and he preached in the United Kingdom, France, Switzerland, Germany, Denmark, Sweden, Norway, and Ireland.

[4] He was buried at Salt Lake City Cemetery and was succeeded in the Quorum of the Twelve by Anthony W. Ivins.