Unonius' letters to Swedish, Danish and Finnish newspapers about pioneer life in America sparked a wave of immigration by Scandinavians to the Midwest.

While living in Waukesha County, Unonius befriended James Lloyd Breck, one of the founders of the Episcopal seminary Nashotah House.

[2] In 1845, Gustaf Unonius became the first graduate of Nashotah House and was ordained to the Diaconate by Bishop Jackson Kemper.

He was later ordained as a priest in The Episcopal Church, continuing to commute from the Pine Lake Settlement for several years.

The stories of his travels to the United States and the trials and tribulations of life on the frontier were the subject of his two-volume memoirs, published in 1862.