He rose to prominence during the mass movement for the unification of Nagorno-Karabakh with Armenia in the late 1980s and led Armenian volunteer groups during the early clashes with Azerbaijani forces.

Appointed defence minister by President Levon Ter-Petrosyan soon after Armenia's independence from the Soviet Union in late 1991, Sargsyan became the most prominent commander of Armenian forces during the First Nagorno-Karabakh War.

After his relations with Kocharyan deteriorated, Sargsyan merged the influential war veterans group Yerkrapah into the Republican Party and joined forces with Armenia's ex-communist leader Karen Demirchyan.

[19] Due to the fact that Sargsyan was popular among Armenian volunteer units and army officers,[20] he was appointed the first Defense Minister of independent Armenia by President Ter-Petrosyan in December 1991.

[27] On 15 August 1992, Sargsyan called on Armenian men to gather and form a volunteer unit to fight against the advancing Azerbaijani forces in the northern parts of Nagorno-Karabakh.

[17] Under the command of Major-General Astvatsatur Petrosyan,[29] it defeated the Azerbaijani forces near the Gandzasar monastery and Chldran village in Martakert Province, on 31 August and 1 September 1992, respectively.

[32] Political chaos in Azerbaijan and the demoralization of the Azerbaijani army resulted in the Armenian forces taking control over the territories outside of the original Soviet-drawn borders of Nagorno-Karabakh.

[50] In July 1995, Vazgen Sargsyan helped Ter-Petrosyan's Pan-Armenian National Movement (PANM) win the parliamentary election and pass the constitutional referendum that gave the president more powers in appointing and dismissing key judicial and legislative officials.

[56] In response, Vazgen Sargsyan stated that "even if they [the opposition] win 100 percent of the votes, neither the Army nor the National Security and Interior Ministry would recognize such political leaders."

"[59] According to Freedom House, Sargsyan was allegedly involved in beating and seriously injuring Ruben (Rubik) Hakobyan, an MP from the Armenian Revolutionary Federation (ARF), after he was arrested during the demonstrations.

[60] In 1997, the OSCE Minsk Group, co-chaired by Russia, the United States and France, pressured Armenia and Azerbaijan to agree on the final status of Nagorno-Karabakh.

[71][72] On 23 January 1998, during the peak of the crisis, Vazgen Sargsyan declared his unconditional support to Robert Kocharyan,[73] and blamed the Pan-Armenian National Movement for trying to destabilize Armenia.

[83][84] He called Kocharyan a "man of unity of word and action" and stated that his experience in Karabakh and Armenia "shows that he is capable of solving economic problems also".

The British Helsinki Human Rights Group suggests that "ordinary Armenians turned to Robert Kocharian as someone untainted by mafia connections and the intrigues of Yerevan politics.

[88] Even after becoming president, Kocharyan did not have any significant institutional support (e.g. a party, control of the army, a source of money) and remained "in a fundamental sense an outsider in Yerevan".

By 1998 Vazgen Sargsyan became "the power behind the throne"[93] as the Yerkrapah faction—made up of war veterans loyal to him—was the single largest faction in the Armenian parliament[94] following Ter-Petrosyan's resignation in February 1998.

[117] ODIHR's final report described the election as "a step towards compliance with OSCE Commitments" and claimed that, along with improvements to the electoral framework and the political environment, serious issues remained.

The National Democratic Institute report was more critical, saying it "failed to meet international standards" and that it proved to be the continuation of the flawed 1995 parliamentary elections, differing only in "the methods and types of manipulation".

[132] Despite being criticized by the opposition, especially the National Democratic Union, the Unity bloc voted in favor (96 of the 131 MPs) of the austerity measures of the Sargsyan cabinet on 28 August, allowing Armenia to take loans from the World Bank and the International Monetary Fund (IMF).

[135] National Assembly Speaker Karen Demirchyan called for a greater role of the state in the economy to ensure stability,[116] while President Kocharyan was mostly uninvolved in these developments.

[138] On 21 September, the anniversary of the day in 1991 when Armenians voted in favor of leaving the Soviet Union in a referendum, a military parade was held in Yerevan's Republic Square.

[142][143] On 27 October 1999, at around 5:15 pm,[144][145] five assailants—Nairi Hunanyan, his brother Karen, their uncle Vram and two others[146]—armed with Kalashnikov rifles hidden under long coats,[144][147] broke into the National Assembly building in Yerevan, while the government was holding a question-and-answer session.

[156][157] A number of high-ranking officials from some 30 countries, including Russian prime minister Vladimir Putin and the Georgian President Eduard Shevardnadze, attended the funeral.

By physically eliminating Karen Demirchyan and Vazgen Sargsyan, its organizers wanted to create prerequisites for Kocharyan's victory in the future presidential elections.

He insisted the shooting was assisted by the Russian secret services to bring the "Neo-Bolshevik criminal clan" of Serzh Sargsyan and Robert Kocharyan into power.

[171] Ashot Manucharyan, one of the leading members of the Karabakh Committee, the former Minister of Internal Affairs and Ter-Petrosyan's National Security Adviser and his close ally until 1993, stated in October 2000 that Armenian officials were warned by a foreign country about the shootings.

According to Razmik Martirosyan, a friend and the Minister of Social Security from 1999 to 2003, Sargsyan promised in December 1987 that he would marry sometime before 8 March of the next year, but did not because the Karabakh movement started in February.

[192] Aram Sargsyan founded the Hanrapetutyun Party in April 2001, along with several influential Yerkrapah members, such as the former Mayor of Yerevan Albert Bazeyan and former Defence Minister Vagharshak Harutyunyan.

His comrades from the Yerkrapah Volunteer Union,[215] high state officials and many others visit the Yerablur cemetery, where Sargsyan is buried next to many Armenian military figures.

Several survey conducted by Gallup, Inc., International Republican Institute, and the Armenian Sociological Association from 2006 to 2008, revealed that Vazgen Sargsyan topped the list of national heroes in public perception, with 15%–20% of the respondents giving his name.