[1] He moved to Oshkosh, Wisconsin, in September 1855, and made the city his primary residence for the rest of his life.

In 1870, he built a factory under the firm name Carlton Foster & Co., which became a major manufacturer for sashes, doors, and blinds.

[1] Through his business activity, Foster became involved in local politics as a member of the Republican Party of Wisconsin.

[2] His last campaign for office was in 1886, when he was elected to his third and final term as mayor, defeating incumbent Democrat Andrew Haben.

In June, he decided to live full-time aboard his beloved steam yacht, the Anna M., believing that the fresh air on the lake and river would improve his health.