Began racing career in Karting, winning Kart Junior Championship in 1990 and 1991 . Ran Formula BMW ADAC in 1993 , taking fourth place in points. Competed in Formula 3 in Germany from 1993-98, placing third in 1998 . After moving in to Formula 3000 for one season in 1999 , switched to Porsche Supercup in 2000 , finising eighth that year. In, 2001, finished sixth in the Porsche Supercup. In 2002 , finished fourth in the Supercup series and sixth in the Carrera Cup. Left the final round of the 2003 Supercup series believing he was Champion, only to be relegated to second when an appeal was heard for a penalty regarding another competitor.
Henzler, who won nine of 12 events (scoring maximum points 11 times) in the Porsche Michelin Super Cup series en route to the Driver’s Championship in 2004 for Farnbacher Racing, captured wins at both races he entered in the 2004 SCCA Pro Racing SPEED World Challenge GT Championship, finding the tracks similar to what he was accustomed in Europe.