In May 2010, he was elected as a Member of Parliament for the newly founded pro-European centre-right party TOP 09, gaining the largest number of preference votes.

He was candidate for President of the Czech Republic in the 2013 presidential election, and qualified for the second round, finishing as runner-up, with 45.19% of the votes.

[6] From 1948 to 1990, he lived in Austria, where he was known as Karl Schwarzenberg, and was involved in politics for the Austrian People's Party and became a noted critic of human-rights violations in the Eastern Bloc, chairing the International Helsinki Federation for Human Rights.

The House of Schwarzenberg originates in Franconia, where the family still owns substantial property,[citation needed] but made Bohemia their primary seat in the 17th century, also maintaining residences in Vienna.

[5] After the fall of the communist regime, Schwarzenberg returned to Prague in 1990, although he still occasionally visited Austria, where part of his family lives.

[15] Schwarzenberg's daughter (conventionally known as Lila Morgan-Schwarzenberg) co-directed and co-wrote a documentary about her father and their strained relationship ("Mein Vater der Fürst") which was released in 2022.

From 1984 to 1991 he was chairman of the International Helsinki Federation for Human Rights, and in 1986 he founded the Dokumentationszentrum zur Förderung der unabhängigen tschechoslowakischen Literatur in Scheinfeld, West Germany.

[18] While a senator, he was expelled from Cuba in May 2005 (together with German MP Arnold Vaatz), where he was due to meet dissidents opposed to the Cuban President Fidel Castro.

[19] Between 9 January 2007 and 9 May 2009, he was Minister of Foreign Affairs of the Czech Republic in Mirek Topolánek's second coalition government.

His nomination by the Green Party caused a small controversy when President Václav Klaus stated that he had strong links to Austria and so would not be able to defend national interests.

[22] According to public opinion polls, he was the most popular politician in the Czech Republic in 2009, and he also usually received the most preferential votes in elections.

On 11–12 January 2013, Schwarzenberg successfully took part in the first round of Czech presidential elections, the first popular vote for presidency of the country.

In the 2013 - 2017 election period, he was the chairman of the Foreign Affairs Committee of the Chamber of Deputies of the Parliament of the Czech Republic.

"[28] In January 2013, while running for President of the Czech Republic, Schwarzenberg stated, referring to the Beneš decrees, that "what we committed in 1945 would today be considered a grave violation of human rights and the Czechoslovak government, along with President Beneš, would have found themselves in The Hague," referring to the International Criminal Court.

[31] A member of the high nobility of Bohemia, his full name was Karl Johannes Nepomuk Josef Norbert Friedrich Antonius Wratislaw Mena Fürst zu Schwarzenberg in German and Karel Jan Nepomucký Josef Norbert Bedřich Antonín Vratislav Menas kníže ze Schwarzenberga in Czech.