Eastman was born February 22, 1806 in Randolph, Vermont, son of Tilton and Experience Smith Eastman. He was college educated (at an Episcopal seminary, which may explain his nickname of "Deacon"), then worked on his father"s farm and helped put two brothers through college as well.
One of these brothers, George B., would later become a minister in Fond du Lac, Wisconsin. The couple would eventually have four children together. He came to Wisconsin Territory in 1846, spending some time in Dodge County before moving on to Oshkosh later that year.
He was appointed postmaster of Oshkosh by the Polk administration in that same year, and would serve until 1849, when Whig Zachary Taylor became President of the United States (postmaster being a patronage position).
In February 1847, Eastman, Miller and other locals were authorized by the territorial legislature to form a company to build a bridge across the Fox River "at Miller"s Ferry" in Oshkosh. With the breakdown of the Second Party System in American politics, Eastman (who had been a Democrat in Vermont) became active in the "Union Democratic Party" movement, which eventually merge with the Free Soil Party.
The district had Waupaca County added to it in the subsequent redistricting, and Eastman was succeeded in that position in the 1851 election by Dudley Blodget, a Whig. (Crary and Blodget were both also from Oshkosh)
In 1853, the new Democratic President Franklin Pierce once more appointed Eastman as Postmaster of Oshkosh.
Also in 1853, Eastman supported the incorporation of the City of Oshkosh, formerly part of the Town of Oshkosh.
He was elected the first mayor of the new city (on a combined Democratic and Independent ticket), and would in later years serve as an alderman as well. He came within one vote of being elected mayor once more (as a Democrat) in 1856, losing with 318 votes to 319 for Thomas A. Follett. Eastman opened a bookstore and stationery store in the summer of 1851 (after the legislative session was over).
Eastman remained Postmaster until 1861, when the newly elected Republican administration of Abraham Lincoln took office.
Eastman died February 23, 1870, at the age of 64 years and one day. He is buried in Oshkosh"s Riverside Cemetery.
Catherine (Granger) Eastman lived until June 18, 1897.
