Following Saturday’s 1-1 draw with Darlington, it has been decided it is time for change at the Impact Arena.
The Reds have failed to live up to expectation this season in the National League North, despite a host of big summer signings including Grimsby captain Craig Disley.
Alfreton are 18th in the table, just a point outside of the drop zone.
Reds chairman Wayne Bradley said: “I want to thank John and his backroom staff for efforts during their time at Alfreton Town. The season has not shaped the way we wanted it’s been a tough season so far. It makes sense for all to move on.
“John, Karl and Chris go with our best wishes for the future and it was a decision the club had to make.”
Following the game with Darlington, the manager said things were looking up for the club.
“Sometimes you have got to keep teams who are in and around you below you. We’ve done that.
“We have been on a bad run, especially at home. We worked very hard and we had three good chances to get a goal in the first half but it just never happened.
“We told the lads to keep believing and they did. Today was vital that we kept going
“Darlington were being tipped to go and win it this season, or at least be in the play-offs. They’ve got a lot of clout. So a 1-1 draw with them is not bad.
“It’s not a turning point, but it keeps us going and it keeps them below us.”