Until 1942, he was involved in minor acts of resistance such as refusing to pay income tax and distributing illegal literature.

Marinus Post, one of Johannes' brothers was involved directly in the resistance, and while at his house in 1942, he met Arnold Douwes and Dr. Cohen.

With the help of Arnold Douwes and Nico Leons, a network for hiding Jews in Nieuwlande and the surrounding area was established.

Johannes would bring Jews to houses and persuade people into giving them shelter, using moral and religious arguments to convince the residents.

He was also helped in this by his role in the community, previously being the deputy major of the local regional council, the head of his large family, and a successful farmer.

These strikes were a response to the Nazis arresting soldiers from the former Dutch army and taking them to Germany to work on Arbeitseinsatz.

Post began carrying out robberies for the resistance, stealing weapons and ammo from police stations and other locations.

In January 1944, Post alongside his compatriots stole supplies in South Holland and Western North Brabant.

Post carried out a huge robbery at Archimedesstraat police station, making away with sixty pistols, ammunition and cartridge holders.

That March the LKP asked him to help coordinate groups in the northern provinces of the Netherlands: Drenthe, Groningen, and Friesland.

In June, the Sicherheitspolizei arrested many resistance leaders in the northern provinces where Post worked which made it too risky for him to return.

Post made plans to break his brother out of the Amsterdam detention center with the help of a Dutch SS guard.

Johannes and twelve other resistance members were driven out to the sand dunes outside Overveen, where they were murdered, then buried together in a mass grave.

Johannes Post and the village of Nieuwlande were recognized as Righteous Among the Nations by Israel in recognition for their efforts to save Jews.