Debut & Jaguar (2004)
Christian entered Formula One with the Jaguar team in 2004, he had a solid if quiet season, finishing all but four grands prix (to Webbers 8 retirements) however when they both did finish, he failed to beat Webber on any occasion. He scored his first points at the Belgian Grand Prix, taking 6th position.
Red Bull Racing (2005-2006)
Late 2004 Red Bull bought out the Jaguar team, the team became Red Bull Racing. Klien continued in his race seat, with new teammate David Coulthard, however initially he was to share the seat with Vitantonio Liuzzi. After a couple of points scoring positions, he kept the seat and raced in 15 of the 19 rounds, notching up 9 world championship points.
2006 was Christian's last year in a race seat, he largely matched his more experienced teammate (Coulthard) throughout the season, however it seemed whenever he was lined up for a good result a mechanical failure took him out of contention. An example of this was in Monaco, whilst running in 5th and running strongly he suffered transmission failure and Coulthard took his position. Coulthard went on to finish 3rd and thus scored Red Bulls first podium.
Late in 2006 Mark Webber signed for Red Bull to partner David Coulthard, thus Klien was to be without a seat the next season. He was offered a seat at a Red Bull-backed Champ Car team, but he declined, wishing to find a F1 seat. As a result he was replaced for the final three grands prix by Robert Doornbos.
Test Driver (2007-present)
Since his time at Red Bull, Christian has been test driver at Honda (2007), and BMW (2008-2009). He also has raced in the American Le Mans Series for Peugeot, taking 3rd at Le Mans 24 hour.
On 5th May 2010, Christian was announced as Hispania's test and reserve driver alongside Sakon Yamamoto. He will drive the F110 in Friday practice in Spain.