The defeat to Hinckley dented Kettering's automatic promotion hopes and Ladak said: "I believe it is our best chance of achieving our promotion aspirations and have made this decision in the best interests of the club."
"Ron felt it would be better for any incoming manager to be able to work from a clean slate."
Atkinson began his managerial career with Kettering in 1971.
He rejoined the club, which had Paul Gascoigne as manager for a 39-day spell last year, in January.
Kettering, who lie second in the Conference North table, have placed coach Danny Nicholls in temporary charge but are set to name a caretaker manager until the end of the season.
Before rejoining Kettering, Atkinson had been out of football since 2004 when he lost his job as an ITV pundit for making a racist comment which was broadcast when he thought he was off-air.