His father, Roman Kreuziger Sr., was also a bicycle racer who won the Tour of Austria in 1991 and the Cyclocross Junior World Championships in 1983.

Kreuziger competed as an all-rounder, with climbing and time trial abilities, becoming a contender for the General classification of stage races.

[7] He turned professional in 2006 with Liquigas after a successful amateur career which saw him win the Junior Road World Championships in 2004 and a stage of the Giro delle Regioni in 2005.

In 2007, he showed great improvements in his abilities by placing second in the prologues of Paris–Nice and the Tour de Romandie, where he also finished sixth overall.

In his first Tour de France, he proved himself as an excellent climber among the world's greats, eventually finishing second in the youth competition, and 12th overall.

He broke free of the lead group with 7 km (4.3 mi) to go and resisted the peloton's surge on the Cauberg, taking a solo triumph.

[15] When asked about the allegations after the Amstel Gold Race, Kreuziger refused to comment on the ties, saying he would address the topic after the Tour de Romandie.

Despite moving into a high finish with Alberto Contador, Kreuziger slipped down to 5th overall after losing ground to Nairo Quintana and Joaquim Rodríguez in the alps.

In June 2014, Tinkoff-Saxo announced that Kreuziger was being temporarily suspended from racing after the UCI questioned abnormalities in his biological passport.

[3] In his first season, Kreuziger took his only victory with the team at the Pro Ötztaler 5500, a one-day race with 5,500 metres (18,000 feet) of climbing.

[27] He failed to record any top-twenty individual finishes, and although he was offered a contract extension for 2022, Kreuziger elected to retire and became a directeur sportif with Team Bahrain Victorious.