He returned to Afghanistan following the Soviet intervention which toppled Amin's rule and placed Babrak Karmal as head of the state, the party and the government.

He remained open to dialogue with the mujahideen and other groups, made Islam an official religion, and invited exiled businessmen back to re-take their properties.

In 1965, during his study in Kabul, Najibullah joined the Parcham (Banner) faction of the People's Democratic Party of Afghanistan (PDPA) and was twice imprisoned for political activities.

On 27 April 1978, the PDPA took power in Afghanistan (Saur Revolution), with Najibullah a member of the ruling Revolutionary Council; however, the Khalq (People's) faction of the PDPA gained supremacy over his own Parcham (Banner) faction, and after a brief stint as Ambassador to Iran, he was dismissed from government and went into exile in Europe, until the Soviet Union intervened in 1979 and supported a Parcham-dominated government.

According to evidence, Najibullah was dependent on his family and his professional network, and more often than not appointed people he knew to top positions within the KHAD.

[26] With the situation in Afghanistan deteriorating, and the Soviet leadership looking for ways to withdraw, Mikhail Gorbachev wanted Karmal to resign as PDPA General Secretary.

[27] Yuri Andropov, Boris Ponomarev and Dmitriy Ustinov all thought highly of Najibullah, and negotiations of who would succeed Karmal might have begun as early as 1983.

The GRU preferred Assadullah Sarwari, earlier head of ASGA, the pre-KHAD secret police, who they believed would be better able to balance between the Pashtuns, Tajiks and Uzbeks.

A meeting in the PDPA in November relieved Karmal of his Revolutionary Council chairmanship, and he was exiled to Moscow where he was given a state-owned apartment and a dacha.

[20] In many ways, the National Reconciliation led to an increasing number of urban dwellers to support his rule, and the stabilisation of the Afghan defence forces.

It began when the government introduced a law permitting the formation of other political parties, announced that it would be prepared to share power with representatives of opposition groups in the event of a coalition government, and issued a new constitution providing for a new bicameral National Assembly (Meli Shura), consisting of a Senate (Sena) and a House of Representatives (Wolesi Jirga), and a president to be indirectly elected to a 7-year term.

Their hopes were dampened when the Najibullah government introduced the state of emergency on 18 February 1989, four days after the Soviet withdrawal due to a mujahideen offensive starting to take shape in Nangarhar Province, later leading to the Battle of Jalalabad.

[49] During a Politburo meeting Eduard Shevardnadze said "We will leave the country in a deplorable situation",[50] and further talked about the economic collapse, and the need to keep at least 10 to 15,000 troops in Afghanistan.

[citation needed] Almost immediately after the Soviet withdrawal, the Battle of Jalalabad broke out between Afghan government forces and the mujahideen, in cooperation with Pakistan's Inter-Service Intelligence (ISI).

The offensive against the city began when the mujahideen bribed several government military officers, from there, they tried to take the airport, but were repulsed with heavy casualties.

By the beginning of 1991, the government controlled only 10 percent of Afghanistan, the eleven-year Siege of Khost had ended in a mujahideen victory and the morale of the Afghan military finally collapsed.

"[65] By January 1992, Najibullah had become internationally isolated, with the loss of his biggest supporter he decided to consolidate his power over the non Pashtuns who were considered less loyal to the regime.

[66] Momin had developed secret ties with the Tajik warlord Ahmad Shah Massoud and was passing on secret information to Massoud which led to Najibullah ordering the sacking of Momin which was carried out by Juma Achak, an Achakzai Pashtun who served as Commander of the Northern Zone and was known to hold Pashtun chauvinist views.

The defectors would form an anti-Pashtun coalition known as the Movement of the North (Harakat-e Shamal) and ally with the Tajik Jamiat-e Islami and Hazara Hezbe Wahdat in taking on the mostly Pashtun, Afghan Military.

Many Tajik Parchamites loyal to Babrak Karmal would defect en masse during the capture of Mazar-i-Sharif including General Mohammad Nabi Azimi with the Pashtun Khalqist and Pro-Najibullah army and paramilitaries defending the city.

The strategic mutiny led by these Ismaili leaders, in collaboration with other non-Pashtun factions, effectively disrupted Najibullah's main supply route from the former Soviet Union, directly contributing to the collapse of his regime.

This pivotal action not only marked a turning point in Afghanistan's history but also highlighted the critical influence of the Ismaili community in shaping the nation's political landscape during a period of profound change and instability.

At the UN compound in Kabul, while waiting for the UN to negotiate his safe passage to India, he occupied himself by translating Peter Hopkirk's book The Great Game into his mother tongue Pashto.

[70] India was placed in a difficult position by deciding to allow Najibullah political asylum and safely escorting him out of the country.

Massoud (a member of Rabbani's Jamiat-e Islami Party) himself claimed that Najibullah feared that "if he fled with the Tajiks, he would be for ever damned in the eyes of his fellow Pashtuns.

[82] Najibullah and Shahpur's bodies were hanged from a traffic light pole outside the Arg presidential palace the next day in order to show the public that a new era had begun.

[82] The perpetrators of the murder have been debated, some including Soviet journalists Plastun and Andrianov who knew Najibullah personally, US Special Envoy to Afghanistan Peter Tomsen, the former National Directorate of Security, Afghanistan's Strategic and Scientific Research Center, and many Pashtun Nationalist including a former senator in Pakistan, Afrasiab Khattak have claimed that Najibullah was assassinated by the ISI (alongside members of the Taliban working for them) allegedly over his Pashtun nationalist stance Durand Line as well as revenge for the botched Battle of Jalalabad in 1989.

[83][84][85] In his book The Wars of Afghanistan, Tomsen wrote, “Najib's entrapment and execution carried the hallmarks of a classic intelligence operation.

[90] On 1 June 2020, following a visit to his grave in Gardez by the Afghan National Security Advisor Hamdullah Mohib, Najibullah's widow Fatana Najib said that before constructing a mausoleum for him, the government should first investigate his assassination.

[102] Najibullah was married on 1 September 1974 to Fatana Najib, principal of the Peace School whom he met when she was an eighth-grade student and he was her science tutor.