The 32-year-old has long been recognised as one of Germany's finest defenders, but has only recently recovered from serious injury and is back in the Bundesliga after a long legal row with his club, Bayer Leverkusen.
Capped 45 times, his inclusion was seen as a tacit acceptance by Klinsmann that his young defence, who came up short in a 4-1 friendly defeat by Italy in March, needed a more experienced anchor.
"Jens is a player who brings a lot of experience to the team," Klinsmann told a news conference.
"He's played in a lot of tournaments before and knows what to expect. Jens will be an important part of the framework."
Nowotny last played for Germany in a 2-1 defeat by Czech Republic that knocked them out of the group stages at Euro 2004.
His return for Leverkusen in the latter stages of the past season were an immediate reminder of his class and were a key factor in his team's strong finish to the campaign.
The other surprise member of Klinsmann's squad was Borussia Dortmund's attacking midfielder David Odonkor, who has yet to win a cap.
"He's a huge talent," said Klinsmann, adding that he had not picked him before to avoid putting pressure on the 22-year-old.
Odonkor took the place of Schalke 04 striker Kevin Kuranyi, who had flashes of brilliance when Klinsmann first took over two years ago but has struggled to find the net in recent months.
Goalkeepers: Jens Lehmann (Arsenal), Oliver Kahn (Bayern Munich), Timo Hildebrand (VfB Stuttgart)
Defenders: Arne Friedrich (Hertha Berlin), Robert Huth (Chelsea), Marcell Jansen (Borussia Moenchengladbach), Philipp Lahm (Bayern Munich), Per Mertesacker (Hanover 96), Christoph Metzelder (Borussia Dortmund), Jens Nowotny (Bayer Leverkusen)
Midfielders: Michael Ballack (Bayern Munich), Tim Borowski (Werder Bremen), Torsten Frings (Werder Bremen), Sebastian Kehl (Borussia Dortmund), Bernd Schneider (Bayer Leverkusen), Bastian Schweinsteiger (Bayern Munich), Thomas Hitzlsperger (VfB Stuttgart)
Forwards: Gerald Asamoah (Schalke 04), Miroslav Klose (Werder Bremen), Oliver Neuville (Borussia Moenchengladbach), Lukas Podolski (Cologne), Mike Hanke (Werder Bremen), David Odonkor (Borussia Dortmund)
