The former Walsall Wood boss will be assisted by Steve Hinks.
Harris, 34, has been involved in management from a young age and has built his reputation amongst the lower local leagues before getting the chance to take over at Walsall Wood just under three years ago.
He led the club to promotion from Step 5 last season, and this term they have consolidated that achievement and currently sit 10th in the Pitching In NPL Midlands Division - helped in recent weeks by a run of five wins in their last six matches in all competitions.
He also guided the club to the first round proper of the FA Trophy for the first time in its history - a run which included a 3-0 victory over his new employers earlier this season.
Harris replaces Danny Glover, who was relieved of his duties in the wake of last weekend's 2-1 defeat at City of Liverpool.
Hednesford have only won once in the Pitching In NPL West Division this season - a 1-0 victory at Newcastle Town in mid-August.
Joining him in the dugout will be 57-year-old Hinks, who has served as a number two at the likes of Tamworth, Nuneaton, Sutton Coldfield, Pelsall, Coalville, Bridgnorth, Rushall and Wolves Sporting.
A supporter of the Pitmen in his younger days, Hinks has also been a huge part of Walsall Wood's recent success.
Hednesford chairman Hayden Dando said: “We knew we had to move quickly to appoint a new manager.
"Everyone can see where we are in the table, however it also had to be the right appointment. We didnt put it out there for CV’s, and we instead spoke to a selection of managers who we targeted as being right for the job.
"Harry’s achievements cannot be ignored, and I felt from meeting with both him and Hinksey that they would be really up for the challenge at the club.
"They both believe we can not only stay up but thrive. We have been able to increase the budget from where we started over the last few weeks thanks to a combination of our attendances, as well as some superb commercial work, so we were able to offer them a budget that they can achieve something with - not just for this season which has to be focused on getting safe in the short term, but also in future seasons to come."
On his appointment, Harris said: “I'm really honoured to be given the opportunity to manage this fantastic football club.
"In my opinion, it’s historically the biggest non-league club in the midlands, so to be appointed manager is a very proud day for me and my family.
"I’m going to give it everything I have in order to start picking up results and putting smiles on faces of the players and fans."
Harris and Hinks took charge of training for the first time on Thursday night and will be in the dugout for Saturday's home game against Stalybridge Celtic.
Photo credit: Hednesford Town