Michelisz won the 2006 Hungarian Suzuki Swift Cup championship and followed that with the Hungarian Renault Clio Cup title in 2007. In 2008 he finished runner-up in the Hungarian SEAT León Supercup and competed in the SEAT León Eurocup, winning a race at Monza and placing fourteenth overall. That Eurocup win earned him a two-round outing in the FIA World Touring Car Championship with the SUNRED Engineering team at Okayama. In 2009 he won the León Eurocup title outright, which earned him a place at the European Touring Car Cup for SEAT Sport. He qualified on pole position and won the first race, eventually finishing third overall behind James Thompson and Franz Engstler.
Michelisz joined the WTCC full time in 2010 with the Zengő-Dension Team in a SEAT León TDI. He gained his first podium at Okayama following a disqualification ahead of him, then took his maiden WTCC victory at Macau in the season finale. He finished ninth in the championship and won the Rookie Challenge. He switched to BMW in 2011, again finishing ninth, with a lone podium at the Hungaroring.
In 2012 Michelisz claimed his first win with BMW at the Race of Hungary, in front of his home crowd, before going on to win the Yokohama Trophy — the independent championship — at Macau in November, a result the Hungarian motorsport community regards as historically significant.
Zengő Motorsport switched to Honda machinery for 2013. Michelisz remained with the team through the end of 2015, winning at Suzuka in 2013 and the Hungaroring in 2015. Honda then signed him as a factory driver for 2016 alongside Rob Huff and Tiago Monteiro. He won again in Japan and finished fourth in the standings. In 2017 he emerged as a genuine title contender but was beaten by Thed Björk of Cyan Racing in a dramatic final weekend in Qatar.
When the WTCC merged with the TCR International Series to form the World Touring Car Cup ahead of 2018, Michelisz joined BRC Racing Team as Gabriele Tarquini's teammate in a Hyundai. He won once, at Slovakia Ring, and finished fourth in the championship while Tarquini became the inaugural WTCR champion.
The 2019 season was Michelisz's career peak. He took five wins and ten podium finishes across the campaign and was crowned WTCR champion at the season finale at Sepang, defeating Honda's Esteban Guerrieri in a thrilling conclusion. The title made him Hungary's most successful touring car driver at the world championship level.
Michelisz extended his dominance in the successor series, the TCR World Tour, winning the championship in both 2023 and 2024, making him one of the most successful drivers in the history of the TCR format worldwide.
Over more than fifteen years at the top level of touring car racing, Michelisz transformed from a nationally successful kart and junior series driver into a world champion. His 2019 WTCR title and back-to-back TCR World Tour crowns in 2023 and 2024 place him among the finest touring car specialists of his era. His long partnership with Hyundai through BRC Racing and his association with the Hungarian Zengő Motorsport team throughout much of his career represent a consistent thread connecting the domestic and international chapters of his career.