Jagersberger immigrated to the United States in 1902, and settled in Racine, Wisconsin. He married Amanda Olle in 1919. He started working at Case Corporation in Racine to develop a car racing program.
He started eighth in the first Indianapolis 500 in 1911 in a Case chassis. The steering knuckle on his car broke and he had to bow out of the race after 87 laps, and finished 31st. The spinning car veered back and forth across the track, down the pit lane, and back on the track. It hit the judges stand, and the judges fled their posts. Jagerberger's riding mechanic flew out of the car and on the track. The next driver on the scene had to avoid the riding mechanic. Several cars were taken out in the melee, including Harry Knight, Herber Lytle, and Eddie Hearne. Knight's riding mechanic was the only person who suffered an injury, but his back fully recovered. The leaders of the race safely navigated through the wrecked cars. The judges milled around the accident scene and did not score. Around this time Ray Harroun did a driver exchange. The incident caused a controversy about if Harroun actually won the race.
He continued to race and in November 1911, in Columbia, South Carolina, he hit the wall rather than hit a car full of tourists traveling from the infield across the track. He was in the hospital for several months, and his left leg was amputated, which ended his racing career.