The relegation-threatened Harriers took the lead when Keith Lowe headed in Ben Whitfield's corner, before Harry White drove in a second six minutes later.
Arthur Gnahoua added a third with a neat finish from inside the box after great midfield approach play.
Kristian Dennis pulled a goal back late on with a free-kick, but Macclesfield have now suffered four straight losses.
Kidderminster are now 23rd in the table, seven points from safety.
Kidderminster scored three first-half goals to beat Macclesfield and make it three league wins in succession.