Josiah Stowell is known throughout Church History as the employer of Joseph Smith. Josiah had hired Joseph to looked for buried Spanish treasure. A rumor that treasure was buried in the area of Harmony, PA. The employment of Joseph was not long, he was only employed to dig for treasure for a couple weeks. Those couple weeks changed the course of the life of Joseph Smith, because it was during that time when he boarded with the Hale family and met his future wife, Emma.
Joseph meeting Emma was not a coincidence, she was exactly what Joseph needed to progress. Josiah Stowell helped Joseph and Emma during this time, you can read more about this here.
While employed by Josiah Stowell, Joseph Smith was charged with being "a disorderly person". Joseph was arrested and a complaint was heard before the Justice of the Peace. The arrest stemmed from Joseph's participation in the attempt to find buried treasure. Joseph was acquitted of the charges.
Josiah Stowell Sr. joined the Church after it was organized. Josiah did not gather in Kirtland with the rest of the Saints, but stayed in New York.
At the end of a letter dated February 17, 1843 from Josiah Stowell Jr. to John S. Fullmer there was a dictated note by Josiah Stowell Sr. in defense of Joseph Smith saying "He ha binn acquainted with him[Joseph] 6 years & he never knew anything of him but what was right also know him to be a Seer & a Prophet & believe the Book of Mormon to be true & all these stores to be false & untrue that is told about Joseph Smith."
References:
"Sacred Places vol 2" by LaMar C. Berrett and Larry C. Porter p. 118-120
https://www.utahsadventurefamily.com/joseph-knight-home-josiah-stowell-home/