Unlike his sister who competes for fun, Jan battles for the money and the prestige titles. He is known for his no-nonsense style and he battles with strength and speed. Jan was scouted at a young age when a typical school brawl in a nearby park caught the attention of Amsterdam's Gym Leader, and connected him with some of country's strongest trainers to grow his skills. He quickly rose through the ranks and is known for being one of the country's best trainers. His first Pokemon was a Chikorita (now a Meganium), and was given to him by the city's professor. However, his ace is his Accelgor.

Jan is notorious for his ways of making money. He frequently uses the Amulet Coin to up the prize money won during battles, and he buys and sells goods from other trainers at a higher selling price. At the family home in Amsterdam, he helps run a special breeding and daycare service for rabbit Pokemon species with his father. When he is away, his father takes on all the duties. Jan wants to take over the family business from him when he retires from competitive battling.