Midfielder Matt Gadsby popped up with the second-half winner as Kidderminster grabbed a crucial win to breathe new life into their relegation fight.
But they had to come from behind and needed the help of an own goal before clinching only their third home win of the campaign.
With Vouchers on offer for Kidderminster's glamour FA Cup tie with neighbouring Wolves, a big crowd was anticipated.
But the attendance of 2605 was not much above normal and appeared to be a slap in the face from disgruntled fans upset by a hike in prices for the January cup tie.
Harriers were caught day dreaming in the opening stages and found themselves trailing to a seventh minute goal.
A long throw from Justin Miller should have been cleared comfortably but teenage Orient defender Gaby Zakauni rose to beat everyone and head home his first league goal.
He was also a tower of strength at the back and it was a severe blow when he was injured and left the action after only 36 minutes.
Orient had suffered only one defeat in their last seven games but looked shaky in defence and needed some heroics from goalkeeper Glen Morris to keep them ahead. He produced a string of fine stops, notably denying Dean Bennett twice and Andy White.
In the 30th minute he was in acrobatic action again to push away a fierce volley from Adie Smith. But when Gadsby turned the ball back into the box Morris found himself wrong footed as his team-mate Mark Peters headed past him and into his own net.
Harriers did all the pressing in the second half and were rewarded in the 65th minute when Gadsby produced a smart finish from 16 yards after Bo Henriksen had whipped in a cross from the right.
There were a few anxious moments in the closing minutes for the home side, but one particular bright spot was a lively final half hour from striker Scott Rickards, signed from non-league Tamworth earlier in the week.