US right-wing political activist Charlie Kirk was part of a constellation of influencers who helped amplify Republican President Donald Trump's agenda, galvanising conservative youth and rising to international prominence with often inflammatory rhetoric focused on such issues as race, gender and immigration.
The shooting came as Mr Kirk, the president of Turning Point, was addressing a large outdoor crowd on the Utah Valley University campus in Orem, Utah.
On Sunday, he headlined an event in Tokyo organised by the far-right Sanseito party, which made big gains in Japan's upper house election in July.
He also recently spoke in South Korea.
Mr Kirk had 5.3 million followers on his X account and drew an audience of more than 500,000 monthly listeners to podcasts of his radio programme, "The Charlie Kirk Show."
He also authored or contributed to several books, including "Time for a Turning Point" and "The College Scam".
In addition to founding Turning Point USA in 2012 with conservative activist Bill Montgomery, Mr Kirk launched Turning Point Action in 2019 as a non-profit advocacy group backing conservative candidates for office.
Turning Point USA, an organisation dedicated to advancing conservative causes on college campuses, was instrumental in driving youth support for Mr Trump in the November 2024 election.
Mr Kirk's Turning Point events were raucous, a mix of apolitical rally, tent revival, rock concert and a professional wrestling match.
Speakers would take the stage backed by ear-splitting anthems and bright pyrotechnics before often high-spirited crowds of thousands.
"No one understood or had the Heart of the Youth in the United States of America better than Charlie," Mr Trump wrote on his online platform Truth Social in announcing Mr Kirk's death.
"He was loved and admired by ALL, especially me, and now, he is no longer with us."
Mr Trump ordered flags flown at half-staff in Kirk's honor.
Kirk was provocative, taking aim at Muslim politicians ,including Minneapolis mayoral candidate Omar Fateh and Islam as a whole.
He expressed xenophobic views of the Islamic world and Islamic culture, pointing to Europe to make his case.
He said in April: "Islam has conquest values. They seek to take over land and territory, and Europe is now a conquered continent."
During an August podcast episode, Mr Kirk accused Democratic lawmaker Jasmine Crockett, who is black, of being part of an"attempt to eliminate the white population in this country."
"The great replacement of white people is far more sinister than any redistricting project," Mr Kirk said.
The son of a counsellor at a mental-health clinic and an architect, Mr Kirk saw his political career propelled with a 2012 op-ed he wrote for conservative media outlet Breitbart that caught the attention of Fox News, according to a February New York Times report.
Fox then booked Mr Kirk to discuss the national debt, the Times reported.
That appearance led to a speech at Benedictine University, where he met Mr Montgomery, a local Tea Party activist.
Mr Montgomery encouraged Mr Kirk to spread his message to college campuses, and registered the name Turning Point USA for Mr Kirk in July 2012.
Mr Kirk is survived by his wife Erika, a former Miss Arizona USA beauty pageant winner, and their two children.
