Although the Transylvanian Saxon population of Sibiu had declined to a tiny minority by the early 2000s, he won a surprise victory and was re-elected by landslides in 2004, 2008, and 2012.

Iohannis became the president of the National Liberal Party (PNL) in 2014, after previously serving as the leader of the Democratic Forum of Germans in Romania (FDGR/DFDR) between 2002 and 2013.

Iohannis's second term was marked by democratic backsliding[4] as well as a slight shift towards illiberalism[5] and a more authoritarian[6] style of government, especially after the 2021 political crisis and the formation of the National Coalition for Romania (CNR).

[22] Born in the old city centre of Sibiu (German: Hermannstadt) to a Transylvanian Saxon family, Klaus Iohannis is the eldest child of Gustav Heinz and Susanne Johannis.

[24] Both his parents as well as his sister emigrated from their native Sibiu/Hermmanstadt to Würzburg, Bavaria in Germany in 1992, acquiring citizenship there under the right of return granted by the German nationality law,[25][26] as most other Transylvanian Saxons after the fall of the Iron Curtain.

[29] In 1989, he married ethnic Romanian Carmen Lăzurcă, an English teacher at the Gheorghe Lazăr National College in Sibiu.

[33] Iohannis has stated that his family settled in Transylvania in present-day Romania 850 years ago, more specifically around 1500[dubious – discuss] in the small town of Cisnădie (German: Heltau), Sibiu County.

On 7 November 2005, Iohannis was nominated as the "Personality of the Year for a European Romania" (Romanian: Personalitatea anului pentru o Românie europeană) by the Eurolink – House of Europe organization.

Subsequently, the PNL, PSD, UDMR, and the small ethnic minorities group in the Parliament presented Iohannis as their common candidate for Prime Minister of an interim government.

However, on 15 October, President Traian Băsescu nominated Lucian Croitoru, a top Romanian economist, as Prime Minister, and charged the latter with forming the country's next government.

Social Democrat leader Mircea Geoană accused Băsescu of trying to influence the upcoming presidential elections by having them organised by a sympathetic government.

A heavily disputed draft law proposed by Nicolae Păun, leader of the Party of the Roma, regarding the amnesty of some misdemeanors and the pardoning of certain penalties was rejected by the Chamber of Deputies at the initiative of Klaus Iohannis and the party he led,[64] after PNL asked the Judiciary Committee 17 times to reject the draft law.

[65] The collaboration with socialist Prime Minister Victor Ponta was praised by both sides at the start of the mandate, but deteriorated thereafter once with foreign visits of the Head of the Executive, without informing the President, but especially with the criminal prosecution of Victor Ponta for 22 alleged corruption charges, prompting Iohannis to demand his resignation from the head of the Government.

Iohannis criticized the Parliament for defending MPs by rejecting the requests of the National Anticorruption Directorate for lifting their immunity, as in the case of PSD senator Dan Șova or Prime Minister Victor Ponta.

Because the Parliament has not implemented the commitments made on 28 January, Iohannis has organised another series of consultations on the state of electoral laws,[73] but also on rejection of Justice requests for approval of arrest or prosecution of MPs.

The topics of other meetings between the president and parties focused on the Big Brother law package and the national defense strategy.

[74] In February 2016, the National Agency for Fiscal Administration (ANAF) sent a notice of evacuation of the headquarters of two TV stations owned by Dan Voiculescu, sentenced in August 2014 to 10 years imprisonment in a corruption case with 60 million euros worth of prejudice.

[75] In this context, Klaus Iohannis stated that ANAF approach in Antena TV Group case is "hasty", "inappropriate" and that "freedom of expression in media can not be suppressed for trivial administrative reasons".

[79] The statement sparked indignation among unionists[80] who accused him of demagogy, considering that during the electoral campaign of 2014 he expressed a favorable position on the issue.

[93][94] Some public figures in Romania, who in the past expressed their support for Klaus Iohannis, have criticized him for his double standard and lack of proper governance.

Under Ciucă's premiership, Romania experienced democratic backsliding,[114] with The Economist ranking it last in the European Union in the world terms of democracy,[115] even behind Viktor Orbán's Hungary.

"[117][118] On 12 March 2024, Iohannis announced his candidacy for the post of Secretary-General of the North Atlantic Treaty Organization (NATO), promising a "renewal of perspective" for the alliance and citing Romania's "deep understanding" of the situation created by the Russian invasion of Ukraine.

[148] On 28 April 2020, a draft legislation favouring the autonomy of Székely Land, submitted by two deputies of the Democratic Alliance of Hungarians in Romania (UDMR/RMDSZ) in December 2019,[149] was tacitly adopted by the Chamber of Deputies, the lower house of the Parliament of Romania, in which the Social Democratic Party (PSD) held a plurality of seats and all whilst the National Liberal Party (PNL) led a minority government.

[155] In a radio interview, Hungarian Prime Minister Viktor Orbán also reacted to the speech, saying "we have never heard such remarks from Romania, not even in the worst, most antidemocratic, tumultuous times".

[156] The president's comments were also criticised by members of the Romanian opposition parties PSD and ALDE, but also by the confidence and supply USR (which has been supporting the PNL minority government since 2019).

Since coming to power in November 2014, has sent several messages of support to prosecutors investigating sensitive cases against politicians accused of corruption.

Through the work and achievements, you've earned the appreciation of the Romanian citizens who want to live in a just society, in a country without corruption, the institutions, elect to represent them and those who perform public functions are actually serving the people.

I am convinced that we will be increasingly more powerful in applying the constitutional principle that nobody is above the law and to align our established practice in countries with democracies that put the citizen at the center of any policy", stated Klaus Iohannis.

[162][163] In terms of LGBT rights and recognition of same-sex unions in Romania, Iohannis has not stated clearly his opinion:[164] Romanian society is not yet ready for a definite answer.

[168] His reaction was praised by international media, including The Washington Post,[169][170] while religious and conservative organizations in Romania have criticized his position on LGBT rights.