Joel Foster was born the youngest of eleven at Meriden, Connecticut, December 15, 1814. He was liberally educated. He came to Edwardsville, Illinois, in 1830, and to Hudson, Wisconsin, then known as Buena Vista, in 1848. After a careful exploration of the surrounding area he built a home in the fall of 1848, at the junction of the two branches of the Kinnickinnic River, just upstream from its falls. His first winter was spent in a cave overlooking the river with his indentured servant, Dick.
Foster was the pioneer settler of River Falls, Wisconsin, a city which grew at the location of the falls of the Kinnickinnic. He built the first dwelling house, raised the first crops, and helped many other pioneers getting started in that area. He filled many position of responsibility, including judge of St. Croix county. During the Mexican-American War he served as a quartermaster in Colonel William H. Bissell's Second Illinois Regiment.
He was known for his Copper Head Democrat political views and was often the subject of scorn by the local newspaper's Republican editor.
Judge Foster was married at Chicago in 1856 to Charlotte Porch.
On August 9, 1885 he died at his home in town after being gored by a dairy bull on his farm, Foster was buried in the Greenwood Cemetery in River Falls, Wisconsin.
A meeting of the county board of supervisors for St. Croix County was held at the house of Philip Aldrich, June 4, 1849. It was voted at the meeting that the treasurer proceed against the persons elected to office in the several towns, also county, who failed to qualify at a meeting of the justices and clerk of county board of supervisors, September 17, 1849, to canvass the vote for county judge at the election held September 3. Ninety-one votes were canvassed, of which Hamlet H. Perkins received 49, Joel Foster 41, and Bailey F. Baldwin 1.