Upon enlisting in Federal Service, Jean Rasczak joined the Mobile Infantry obtaining the rank of Private. It was at this time that the United Citizen Federation learned of the existence of the Arachnid species, and the Recon Cruiser Cortez was deployed to Klendathu to attempt to make first contact. Private Rasczak was onboard the Cortez for this mission as part of a Mobile Infantry escort for non-military personal. Several probes crashed onto the planet's surface during this mission and it was decided to send a shuttle to the surface with several non-military personnel and their Mobile Infantry escort which include Rasczak. The probe was found an attempt to remove it were made, however, suddenly hundreds of Warrior Bugs appeared and engaged the humans. A hasty retreat was made to the shuttle after several casualties and the humans abandoned their surface mission. Just before leaving, however, Private Rasczak's arm was grabbed by a Warrior Bug which tried to drag him out of the shuttle. Knowing he had no other option to save himself, Rasczak had the shuttle door closed, slicing off his arm, but allowing the shuttle to escape. Despite his serious injury, Jean Rasczak recovered, but was unable to continue as part of the Mobile Infantry. The United Citizen Federation, however, got him another job as a teacher of History and Moral Philosophy.
Jean Rasczak visited the unsanctioned colony Port Joe Smith on Dantana which had been founded by Mormon extremists in the Arachnid Quarantine Zone. During his visit, the Arachnids attacked Port Joe Smith, forcing Rasczak to flee on a ship with several other survivors.
Jean Rasczak for the mean time remained as a teacher in a school in Buenos Aires where John Rico, Carl Jenkins, Carmen Ibanez, and Dizzy Flores were all students of his.
After the Bug Meteor crashed on Earth, Rasczak was re-enlisted in the Mobile Infantry and given a fully functional prosthetic arm and the command of the Roughnecks during several missions in the Klendathu system, including a raid on Tango Urilla.
Later, Rasczak's unit was given a mission to the Whiskey Outpost on the Planet P. Shortly after arriving the outpost, his unit was attacked by an overwhelming Arachnid force. During the battle, he fell into a sand hole created by a Tanker Bug and lost his legs. After his injury, he ordered Rico to kill him, which Rico did by shooting him in the heart before his corpse was consumed by the sand.