In 2015, the South Dakota Supreme Court appointed Johnson to the Second Judicial Circuit to replace Judge Joni Cutler.
[3] During her time on the bench, Johnson was a member of the Minnehaha County Veteran's Treatment Court and served on pre-trial detention and release committees.
In May 2018, she left the judiciary and returned to the Minnehaha State's Attorney's Office.
In 2019, the presiding judge of the Second Circuit Court, Robin Houwman, appointed Johnson the interim Minnehaha County State's Attorney after Aaron McGowan resigned.
[5] Johnson is also a part-time adjunct professor of political science at the University of South Dakota.