In 2015, Southern was a candidate in the 2015 Canadian federal election representing the Libertarian Party in the district of Langley—Aldergrove. She was briefly removed by the party as a candidate, but was eventually reinstated with support from Breitbart News and The Rebel Media. The election was won by Conservative candidate Mark Warawa. Southern finished last, having received 535 votes, or 0.9% of the total.

In June 2015, while reporting on the Vancouver SlutWalk for The Rebel Media, Southern’s cameraman was shoved and Southern’s protest sign stating “There Is No Rape Culture in the West” was torn up.

Southern has spoken in opposition to feminism and has said that women are “not psychologically developed to hold leadership positions”, and “not going to be as great being CEOs”. In 2015 she attended SlutWalk and held a sign that read, “There is no rape culture in the West.” She also said that it was “insane” to focus on the issue.

In March 2016, a protester in Vancouver poured an unknown liquid over Southern’s head while she was engaging with LGBTQ protesters at a rally in Vancouver, arguing for two human genders.

In October 2016, Southern had her gender legally changed to male as part of a video produced for The Rebel Media to show the ease of Ontario’s new gender ID laws.

In 2016, Southern authored and self-published Barbarians: How Baby Boomers, Immigrants, and Islam Screwed My Generation.

In January 2017, Southern posted to Twitter incorrect rumours from the website 4chan that the Quebec City mosque shooting had been carried out by Syrian refugees; she later deleted those tweets. In March 2017, Southern announced she would be leaving The Rebel Media to become an independent journalist. In the same month, she gained access to White House press briefings.

In April 2017, Southern was one of several scheduled speakers at a Patriots’ Day rally in Berkeley, California. The rally led to a riot between pro-Trump demonstrators and anti-Trump counter-protesters.

In May 2017, Southern, along with Martin Sellner and Brittany Sellner (nee Pettibone), took part in an attempt organized by the Identitarian group Génération identitare to block the passage of an NGO ship, the Aquarius (co-owned by SOS Mediterranée and by Doctors without Borders), which was leaving Sicily to start a search-and-rescue mission for ship-wrecked refugees and migrants off the shores of Northern Africa. Claiming that the goal of the activists “was to stop an empty boat from going down to Libya and filling up with illegal migrants”, Southern was briefly detained by the Italian Coast Guard. NGO ships often rescue migrants and refugees, who disembark from Libyan shores on unsafe makeshift rafts, and bring them to Sicily. Regarding her actions, Southern stated: “if the politicians won’t stop the boats, we’ll stop the boats.”

Southern supported similar actions by Defend Europe, which chartered a vessel to track and stop what it called collusion between NGOs and human traffickers. In July 2017, Southern revealed that Patreon had deleted her account citing concerns about her “raising funds in order to take part in activities that are likely to cause loss of life”. Southern denied these allegations, stating that Defend Europe’s actions were likely to save lives and that none of her funding went towards the group.

In November 2018, Southern released a video that appeared to show an NGO worker admitting that she had coached asylum seekers on how to speak to immigration officials in order to gain refugee status. BuzzFeed News reported that a UNHCR spokesperson said: “Greece has rigorous asylum procedures in place, within a robust legal framework.” In May 2019, Southern released a YouTube documentary, Borderless, about the refugee and migrant crisis. The film was temporarily taken down by YouTube.

In February 2018, Southern, along with Brittany Pettibone and Caolan Robertson, distributed flyers in the English town of Luton describing Allah as “gay”, as part of a “social experiment” video.

In March 2018, Southern, Pettibone, and Identitarian activist Martin Sellner were all denied entry to the United Kingdom. Southern was also questioned under the Schedule 7 of the Terrorism Act 2000. Her denial of entry was due to her intentions during her March visit and on the same grounds as Pettibone and Sellner.

Shortly before a planned speaking tour of Australia in July 2018, Australia’s Department of Home Affairs denied Lauren Southern an Electronic Travel Authority visa, saying it was “not a working visa”. She intended to charge $79 for a basic ticket and up to $749 for an “intimate dinner”. The Australian government allowed her to enter the country once she had the correct visa. Arriving at Brisbane airport, she was wearing an “It’s OK to be white” shirt.

In July 2018, Southern applied for a travel visa to visit New Zealand for a speaking tour with Canadian podcaster and YouTuber Stefan Molyneux. Immigration Minister Iain Lees-Galloway described their views as “repugnant”, but said they met immigration character requirements and cleared their entry. The pair had not secured a venue, as Auckland Council had cancelled their initial booking, citing health and safety concerns. The pair briefly cancelled and then resumed the tour over difficulties with the venue. The subsequent booking of a private venue was revoked by its owners. In retaliation, their venue was vandalised. The failure to find a venue was celebrated by around 1,000 protestors, who said the planned event had nothing to do with freedom of speech. Prime Minister Jacinda Ardern said Southern’s views “are not those that are shared by this country”.

In August 2018, the Mayor of Auckland Phil Goff tweeted that Council venues should not be used to “stir up ethnic or religious tensions”, and that “we’ve got no obligation at all” to provide a venue for hate speech. For agreeing with the cancellation, an MP received threats of violence.

Southern has been cited as a proponent of white genocide conspiracy theory. In 2018, Southern produced a documentary called Farmlands which claimed that racially motivated farm attacks in South Africa may represent an impending genocide, a common talking point for white nationalists. While producing the documentary, Southern worked with Charlottesville Unite the Right rally attendee Simon Roche, a spokesperson for the racist, ethnonationalist (völkisch) Afrikaner organization Suidlanders. In 2017, Southern produced a video on the Great Replacement conspiracy theory, which posits that non-white immigration will lead to a “genocide” of white Europeans. Southern’s video is credited with helping to popularize the conspiracy theory.

On 2 June 2019, Southern announced her retirement from political activism in her website. She stated that her reasons for leaving were that she needed to move on and find fulfillment in a more private capacity. On 19 June 2020, Southern announced in a YouTube video her return and new plans, expressing some remorse for her previous hardline stances. She was invited to speak at the Australian Conservative Political Action Conference (CPAC) 2020, to be held on 4 November 2020, but in October 2020 it was announced that her invitation had been rescinded by the organisers.

In a documentary about the alt-right produced by The Atlantic, “Southern admits late in the film that her [then] boyfriend, with whom she’s having a baby, is not white.” On 29 January 2020, Southern posted on Instagram announcing that, since her leaving public life, she had married and given birth to a son, while also announcing a desire to keep her family life private. As of 2020, she lives in Sydney, Australia with her Australian husband.