His father was a member of the Slovene Home Guard from Dobrova near Ljubljana who had escaped communist retaliation due to his young age.

He became president of the Committee for Basic People's Defence and Social Self-Protection of the League of the Socialist Youth of Slovenia  [sl] (ZSMS).

[25] Janša was expelled from the party in 1983 after breaking with Yugoslav military orthodoxy by criticizing the system of people's self-defense from a radical left perspective.

[48] Janša's trial was conducted in camera, with no legal representation for the accused, and in Serbo-Croatian (the official language of the Yugoslav Army) rather than in Slovene.

[49] Janša was sentenced to 18 months imprisonment,[48] initially at Dob, but, following public outcry, he was transferred to the open prison in Ig.

[50] The case became known as the JBTZ affair and triggered mass protests against the government, and accelerated the process of democratization,[48] known as the Slovenian Spring.

The Committee for the Defence of Human Rights was formed following Janša's arrest, which became the largest grassroots civil society organization in Slovenia, gaining over 100,000 members within weeks.

[45] As a protest against the League of the Socialist Youth of Slovenia's decision not to postpone the elections, Janša's broke all relations with the organization.

Following the first free elections in May 1990 he became the minister of defence in Lojze Peterle's cabinet, a position he held during the Slovenian war for independence in June and July 1991.

Together with the Minister of Interior Igor Bavčar, Janša was the main organizer of Slovenia's strategy against the Yugoslav People's Army.

[60] In 1994, Janez Janša was dismissed by Prime Minister Janez Drnovšek from his role as Defence Minister because of his involvement in the Depala Vas affair (which centered around an incident in which military personnel arrested and mistreated a civilian off-duty undercover police associate that was attempting to obtain classified documents about the Ministry of Defence).

In a press conference shortly prior to the article's publication, Janša pointed to documents detailing these police plans to secure state institutions to argue that a coup was in fact afoot against his Ministry.

Janša's former friend and fellow dissident Spomenka Hribar argues that his campaigns seem like conspiracy theories, and emphasize emotion, especially patriotic fervor, over rationality.

[79] The notion of "Udbo-Mafija", a term coined by the architect Edo Ravnikar[80] to denote the illegitimate structural connections between the post-communist elites, is particularly prevalent in Janša's thought.

[82] The writer Drago Jančar similarly interprets the animosity against Janša as unjustified reactions of a culture unused to conservative political discourse.

[83] Ahead of the 2004 electoral campaign, Janša turned towards moderation, tempering his radical language and attacks against alleged communists.

[86] In the beginning of December 2011, several clips of the recordings of closed sessions of the Government of Slovenia during the term of Janez Janša were published on the video-sharing website YouTube.

[90][91][92] Janša rejected all accusations as a media conspiracy concocted by left-wing Slovenian journalists, and demanded YLE to provide evidence or to retract the story.

[93] Janša's naming of individual journalists, including some of those behind the 2007 Petition Against Political Pressure on Slovenian Journalists, and the perceived use of diplomatic channels in an attempt to coerce the Finnish government into interfering with YLE editorial policy, drew criticism from media freedom organizations, such as the International Press Institute[94][95] and European branch of International Federation of Journalists whose representative, Aidan White, IFJ general secretary, said "The (Janša's) government is distorting the facts, failing to tell Slovenians the truth and trying to pull the wool over the eyes of the European public about its attitude to media".

[105] During his second term as prime minister, which lasted only one year, Janez Janša responded to the weakening of Slovenian economy during the global economic crisis and European sovereign-debt crisis with opening up old ideological fronts against liberal media, and against public sector – especially educational and cultural sectors, accusing them of being under influence of members of old regime (called Udbomafia and "Uncles from Behind the Scenes" (In Slovene: "strici iz ozadja")[106]) and against everyone who doubted that austerity measures forced upon Slovenia are right ones.

[117][118][119] On 27 February 2013, Janša's government fell, following a vote of no confidence over allegations of corruption and an unpopular austerity programme in the midst of the country's recession.

Gregor Virant welcomed the outcome of the vote, stating that it will enable Slovenia to move forward, either to form a new government or to call for an early election.

[125] The following day, the Minister of Justice, Senko Pličanič, emphasised that the court ruling was not yet binding and therefore Janša was still presumed innocent.

[131] The influential German centre-right wing newspaper Frankfurter Allgemeine Zeitung reported the following day that the domestic Slovene and the international law experts recognised large violations of Janša's rights in the court case.

[143][144][145][146][147][148] The document's plans and ideas were heavily criticized and reacted to by many political leaders from Bosnia and Herzegovina, Serbia, Croatia, Montenegro, Slovenia and as well as by politicians from the European Union and Russia, including Russian minister of foreign affairs Sergey Lavrov[149] and the European Commission's Vice-President and EU's High Representative for Foreign Affairs and Security Policy, Josep Borrell.

[151] After hearing news about the document, Janša spoke in a telephone call with Džaferović, stating that "there is no non-paper regarding border changes in the Western Balkans" and adding that he supports "the territorial integrity of Bosnia and Herzegovina.

[172] Janša is known as a prolific Twitter user, earning him the nickname Marshal Twitto (a reference to the honorary military title of (Marshal) Josip Broz Tito[174]),[174][175][176][177][178][179][180] Janša tends to be pugnacious in his interactions on the site,[174][181][182][183] with one commentator describing him as "[...] using social media to insult journalists, political opponents, the general public, and anybody who does not agree with him",[184] and The New York Times describing him as "[...] setting the benchmark for intemperate social media messaging by a national leader".

[193] After Janša accused her of leaving SDS because it didn't meet her demand to stand as the party's candidate for the 2019 European Parliament election, Ušaj accused him of lying and released a screen capture of a conversation between her and Janša in which he requested that "they" should astroturf an anti-immigration protest on the day that parliament was to discuss an SDS proposal for a referendum on immigration, explaining that "protests are effective if the action comes from below and appears to be a spontaneous uprising".

In 2008, it was reported by the newspaper Mladina that Janez Janša copied a speech by Tony Blair, the prime minister of the United Kingdom.

A few of these sentences were proclaimed the Spade of the Year by the newspaper Večer in 2006; the award is given annually to the best publicly expressed thought in Slovenia.