[2] When first elected to the Assembly in 1873 from the 4th Dane County Assembly district (towns of Blue Mounds, Fitchburg, Madison, Middleton, Montrose, Oregon, Perry, Primrose, Rutland, Springdale, and Verona), Johnson had been a justice of the peace for thirteen years and town treasurer for seven years.
[4] He was re-elected in 1874 as part of the Reform Party (a coalition of Democrats, reform and Liberal Republicans, and Grangers formed in 1873, which secured the election of one Governor of Wisconsin and a number of state legislators) with 1,191 votes to 987 for former Republican Assemblyman Phineas Baldwin, and moved to the committee on assessment and collection of taxes.
[5] He was re-elected in 1875 as a Reformer, with 1,155 votes to 987 for Republican Halle Steensland; and moved to the committee on state affairs.
[6] After a redistricting, he was once again re-elected in 1876 as a Reformer from the new 1st Dane County district (Towns of Berry, Black Earth, Blue Mounds, Cross Plains, Dane, Fitchburg, Mazomanie, Middleton, Montrose, Perry, Primrose, Roxbury, Springdale, Springfield, Verona, Vermont and Westport), with 2,681 votes to 1481 for Republican R. Cowdrey.
In October 1893 the new President appointed Johnson assistant revenue collector for the second district of Wisconsin; he continued in that job until the end of January 1900.