Harriers started the match brightly, with Nathan Blissett and Cheyenne Dunkley going close to opening the scoring, but Gateshead had their own moments in the final third as a Jon Shaw effort was kept out by Danny Lewis.
The deadlock was broken just nine seconds into the second half as Kidderminster took the lead. Craig Reed combined with Blissett before providing a clinical finish to surprise the North-East side.
Three minutes later, Kidderminster took full control at Aggborough as Blissett doubled their advantage after getting onto the end of a delivery from Marvin Johnson.
After recovering from a slow start to the half, Gateshead gradually began to find their feet again, and they pulled a goal back on 64 minutes through Shaw, who nodded home from close range after Kidderminster had failed to deal with a cross.
Harriers made a couple of changes to try to prevent Gateshead building a head of steam, but the visitors continued to push forward with Alex Rodman having a free kick saved by Lewis.
However, the home side were able to hang on to overtake Gateshead in the league table.