Gurpatwant Singh Pannun is one of the main leaders of the Khalistan movement, which advocates for a religion-based separate state to be split out from Punjab and many neighbouring areas in India, to be known as Khalistan. He is the legal advisor and spokesperson for Sikhs for Justice (SFJ), which aims to promote the idea of a separate Sikh state. As of July 2020, the Ministry of Home Affairs of India has declared Pannun a terrorist on the grounds of sedition and secessionism, and has requested an Interpol red notice for him.

Pannun was born and brought up in Khankot village at the outskirts of Amritsar, Punjab, India. As of 2023, he described himself as a dual citizen of the United States and Canada.

Pannun has been actively involved in lobbying for the cause of Khalistan and has been organizing events and rallies in different parts of the world, including the United States, Canada, and the United Kingdom. He has also been involved in filing lawsuits against Indian officials and institutions in international courts, alleging human rights violations against Sikhs.

Pannun has claimed responsibility for various terror incidents in India. In April 2023, in a video, he issued a threat to the Prime Minister of India Narendra Modi during his visit to Assam. In June 2023, various news outlets speculated that Pannun went into hiding after the death of three other prominent Khalistani leaders in 2 months.

In October 2023, Pannun threatened to carry out a Hamas-like attack on India against the backdrop of the Israel-Palestine war. According to the BBC, Pannun has released hundreds of videos censuring India and offering monetary rewards to people who write anti-India graffiti or hoist Khalistan flags on government buildings or desecrate the Indian flag. In September 2023, he was recorded calling for the "political death" of Prime Minister Modi and two of his ministers. Pannun has also claimed responsibility for posters which read "kill India" along with the names and pictures of Indian diplomats. He has denied that the posters incite violence against the diplomats.

In September 2023, a video surfaced in which Pannun warned Indo-Canadian Hindus to leave Canada, further accusing them of having "repudiated their allegiance to Canada". The video elicited widespread condemnation from Canadian politicians. Federal party leaders, Pierre Poilievre and Jagmeet Singh, along with ministers in the federal cabinet, denounced the video. Canada's Public Safety Minister, Dominic LeBlanc, described the video as "offensive and hateful".

In November 2023, Pannun issued threats of danger to individuals planning to travel by Air India on 19 November (the date of the 2023 Cricket World Cup finals). In a video widely circulated on social media, he stated: "We are asking the Sikh people not to fly via Air India on November 19. There will be a global blockade. On November 19, don't travel by Air India or your life will be in danger." In response, the Bureau of Civil Aviation Security of India directed airport operators in Delhi and Punjab, India to prohibit the entry of visitors in airports. Shortly after, Canada's Transport Minister, Pablo Rodriguez and the Royal Canadian Mounted Police (RCMP) announced an investigation into the threats. Spokesperson, Kristin Kelly, stated that the RCMP was collaborating with domestic and international partners and "industry stakeholders" in an investigation into "the threat against Air India flights." Pannun stated that his message was about boycotting, not bombing Air India; he subsequently offered a $100,000 cash reward for a citizen's arrest of the Indian High Commissioner, Sanjay Verma, accusing him of misrepresenting his earlier statements on Air India.

In November 2023, the British newspaper Financial Times (FT) reported that the United States authorities had "thwarted" a plot to kill Pannun in the United States, and the federal prosecutors had filed a sealed indictment against a suspect in a New York district court. The FT also reported that the US had issued a diplomatic warning to India over concerns that the Government of India was involved in the plot. The report came two months after Canada accused Indian agents of being involved in the murder of Hardeep Singh Nijjar. A White House spokesperson confirmed the US had informed India about the incident sometime after the Indian prime minister Narendra Modi's visit to the US in June 2023. The Indian foreign ministry spokesperson Arindam Bagchi stated that the Indian authorities were examining the US inputs.

Following this in December, Pannun issued a statement threatening to "shake the foundation" of the Parliament House in New Delhi on or before 13 December which is the same day as the 2001 Indian Parliament attack. The Delhi Police stated they were aware of the situation and that precautionary measures would be taken "to prevent any untoward incident".

According to various Indian news reports in January 2024, Pannun made veiled threats to the incumbent Chief Minister of Punjab, Bhagwant Mann. In a video, Pannun compared Mann to former Chief Minister, Beant Singh, who was assassinated by Sikh militants. He further urged gangsters within the state to join the organization, Sikhs for Justice, to prevent Mann and other politicians from hoisting the Indian flag during Republic Day events, and to get recognized as "martyrs". In another video he allegedly addressed Prime Minister Modi by saying: "I dare Modi, you come to Delhi without your security. If you are a popular leader, come to Delhi on R-Day without security and SFJ is going to avenge the assassination of Shaheed Nijjar by raising the Khalistan flag," According to Punjab Police, Pannun is a frequent issuer of threats and appropriate measures are taken to deal with them.

On October 11, 2024, in response to the Deputy Minister for Foreign Affairs of Canada, David Morrison, stating that India's territorial integrity must be respected during a public hearing of the Canadian Foreign Interference Commission on October 4, Pannun released a video calling for the balkanization of India before the centennial of Indian Independence Day and threatened to initiate separatist movements in various parts of India, including Jammu and Kashmir, Assam, Manipur, and Nagaland. In the same video, he called on the Chinese Army to seize the Indian state of Arunachal Pradesh, referring to the state as "the territory of China." Vikash Yadav, a former RAW official, was charged by the US with attempted murder of Pannun.

On October 20, 2024, Pannun made a threat towards travellers on Air India, warning against flying on the Indian flag carrier. News reports conflict on the threats, with India Today saying he warned against flying on November 1 to November 19, and News18 India saying he warned against flying after November 19. Sikh militants and terrorists had carried out the bombing of Air India Flight 182 and attempted the bombing of Air India Flight 301, which failed as the bomb exploded at Tokyo Narita International Airport.

In 2020, Pannun was declared a designated terrorist by Government of India and his agricultural land was attached under Section 51A of Unlawful Activities (Prevention) Act. Pannun is facing 22 criminal cases, including three of sedition, in Punjab, India. In October 2022, Interpol rejected India's second request to issue a Red Corner Notice on terror charges against Gurpatwant Singh Pannun, on the grounds of insufficient information.

The NIA alleges that Pannun plays a significant role in "promoting and commissioning terror acts and activities, and spreading fear and terror in Punjab and elsewhere in the country through his threats and intimidation tactics."