After starting his career at the little-known FV Hofheim/Ried, Hildebrand joined the Stuttgart youth team in 1994. In the 1999–2000 season, Hildebrand played in six Bundesliga matches. From the summer of2000, he was the club's number one goalkeeper and contributed largely to Stuttgart's successes, particularly as part of what became known as "Stuttgart's young wild ones" team under coach Felix Magath. He began the 2000–01 season by playing in eight matches in the Intertoto Cup. He went on making 32 Bundesliga appearances, five German Cup appearances, and eight UEFA Cup. The following season, he made 34 appearances. VfB Stuttgart managed to be Bundesliga runners-up in 2003. He had made 20 Bundesliga appearances, one German Cup appearance, four UEFA Cup appearances, and eight Intertoto Cup matches. He survived the Champions League group stage the following season, before bowing out to Chelsea FC in the second round. He made 43 appearances during the 2003–04 season. Hildebrand also played a significant role in Stuttgart's victorious 2006–07 Bundesliga campaign, figuring as a backbone for the next generation of "wild ones" like Serdar Tasci or Mario Gómez and helping Stuttgart provide the third-best defence of the season. The 2006–07 campaign remains his greatest domestic success to this day, and his last season with Stuttgart as in December 2006 he did not accept the club's offer to extend his contract. He made 39 appearances during the 2006–07 season.
Hildebrand joined the Spanish club Valencia on a free transfer on 3 July 2007, with Valencia unveiling Hildebrand via a news conference the next day on 4 July 2007. He stated in the news conference that he would "give everything" to the club. Hildebrand was being viewed as a replacement to the club's long-serving goalkeeper Santiago Cañizares. He made his debut for Valencia on 29 August, for the third qualification round second leg of UEFA Champions League against IF Elfsborg. He played the full 90 minutes of that game of which they won 2–1. Hildebrand was Valencia's first-choice goalkeeper for most of the 2007–08 season, collecting a Copa del Rey trophy on the way. After the departure of manager Ronald Koeman, Hildebrand lost his place in the first team as Koeman's successor Unai Emery preferred newly signed Renan Brito. According to media coverage, Hildebrand refused consignment to the bench and was eventually cut from the squad altogether. Hildebrand had not been playing for Valencia for several months since the Supercopa de España second leg on 24 August 2008. On 4 December 2008, he left Valencia by mutual consent.
Hoffenheim
On 10 December 2008, Hildebrand signed for the Bundesliga side 1899 Hoffenheim. He made his Bundesliga debut for Hoffenheim on 31 January 2009 in their 2–0 win at home to Energie Cottbus, being substituted in the 60th minute due to an injury. During the 2008–09 season, he made 14 appearances. During the 2009–10 season, he made 32 appearances. In summer 2010, Hildebrand left Hoffenheim.
Sporting
Hildebrand signed a one-year deal with Portuguese club Sporting CP and debuted on 16 October 2010 in a 2–1 win over GD Estoril Praia in the Portuguese cup. After Hildebrand left Sporting, he was on trial with Manchester City on their pre-season tour of USA before the 2011–12 season, but they did not take up the option to sign him.
On 25 September 2014 Hildebrand signed for Eintracht Frankfurt in the wake of a major injury to their first-choice keeper Kevin Trapp. He made three appearances. This final top-flight matches for Eintracht were the last of over 300 Bundesliga appearances for Hildebrand.
International career
After collecting 18 Under-21-caps, Hildebrand made his full international debut for Germany on 28 April 2004 in a friendly against Romania in Bucharest as he came on as a half-time substitute for Oliver Kahn with Germany 0–4 down, and eventually lost 1–5. Hildebrand was selected for three consecutive tournaments for Germany, Euro 2004, 2005 Confederations Cup and 2006 World Cup, as Germany's third-choice goalkeeper behind Jens Lehmann and Oliver Kahn. He played his first competitive international at the 2005Confederations Cup against Argentina. He was the only member of the 2006World Cup squad who did not play at the tournament, as Germany came third on home soil. After Kahn's retirement from international football in 2006, Hildebrand stepped up to become Germany's number two and was Jens Lehmann's natural replacement during the Euro 2008 qualification. Somewhat surprisingly, Joachim Löw dropped Hildebrand from the final squad for the tournament and picked Robert Enke and René Adler ahead of him. Although Löw stated that Hildebrand was an important player and may return to the set-up in near future, he never appeared for Germany since his omission from their squad for Euro 2008.
