Highest salary at Johnson County in year 2017 was $128,959. Number of employees at Johnson County in year 2017 was 81. Average annual salary was $30,117 and median salary was $25,184. Johnson County average salary is 36 percent lower than USA average and median salary is 42 percent lower than USA median salary. From 2016 to 2017, the median salary increased 1.4 percent.