Between 1838 and 1840, Fielding was left in charge of the mission when Kimball and Hyde returned to America in the spring of 1838. He acted as Mission President for the church, with Willard Richards as his first counselor and recent British convert William Clayton as his second counselor. Fielding married a newly baptized church member, Hannah Greenwood, on June 11, 1838. Willard Richards was a witness to his marriage and Joseph was a witness to Willard's marriage to Jenetta Richards. Joseph and Hannah had six children, two of them born in Preston: Rachel on 27 June 1839, and Ellen on 2 September 1841.