On the night of 1 July 2015, Cecil was lured out of the protected area and wounded with an arrow by Walter Palmer, an American recreational big-game trophy hunter,[2][3][4] then tracked and killed with a compound bow the following morning, between 10 and 12 hours later.

[6] Palmer had purchased a hunting permit and was not charged legally with any crime; authorities in Zimbabwe have said he is still free to visit the country as a tourist, but not as a hunter.

[9] It resulted in international media attention and caused outrage among animal conservationists, criticism by politicians and celebrities, and a strong negative response against Palmer.

According to Wayne Pacelle, then President of the HSUS, Cecil had "changed the atmospherics on the issue of trophy hunting around the world", adding, "I think it gave less wiggle room to regulators.

[19] The lions in the park, including Cecil, have been studied by scientists from the Wildlife Conservation Research Unit at the University of Oxford as part of a scientific project that has run since 1999,[20] and his movements had been followed since 2008.

[28][29] During June 2015, Walter J. Palmer, an American dentist and recreational game hunter,[30] reportedly paid US$50,000 to a Zimbabwean professional hunter-guide, Theo Bronkhorst, to enable him to kill a lion.

[6][31] In the late afternoon of 1 July, Bronkhorst and wildlife tracker Cornelius Ncube built a hunting blind in Atoinette Farm, a private property owned by Honest Ndlovu just across a railway track from the park.

The hunters tracked the wounded lion and killed him with a second arrow the next morning (about 10 to 12 hours later) at a location less than 250 metres (270 yd) from the initial shot.

[33] Biologist Andrew Loveridge alleged that Palmer's companions (Bronkhorst and Ncube) dragged the carcass of an African elephant killed earlier in the week to roughly 300 metres (330 yd) from the park to bait Cecil out of the protected area.

This interpretation of events was corroborated by the subsequent investigation by Zimbabwe National Parks and wildlife management and is consistent with the satellite data.

"This killing is a huge loss to our tourism sector that was contributing immensely to the national wealth", said Emanuel Fundira, the president of the Safari Operators Association of Zimbabwe.

"[29] At a press conference on 31 July 2015, Zimbabwe's environment minister, Opa Muchinguri, said the hunter violated Zimbabwean law and needs to be held accountable.

"[47][48] Jean Kapata, Zambia's minister of tourism, said "the West seemed more concerned with the welfare of a lion in Zimbabwe than of Africans themselves", and added that "In Africa, a human being is more important than an animal.

[60] After Mia Farrow received criticism for tweeting Palmer's office address, Bob Barker defended her action, saying, "The animal rights movement has just made humongous strides.

Goodwell Nzou, an African PhD student in the U.S., wrote in The New York Times: "In my village in Zimbabwe, surrounded by wildlife conservation areas, no lion has ever been beloved, or granted an affectionate nickname.

"[62] The killing of Cecil sparked a discussion among conservation organisations about the ethics and business of big-game hunting and a proposal for bills banning imports of lion trophies to the U.S. and European Union.

[69] Safari Club International responded by suspending both Palmer's and Bronkhorst's memberships, stating: "those who intentionally take wildlife illegally should be prosecuted and punished to the maximum extent allowed by law.

"[70] Late-night talk-show host Jimmy Kimmel, choking up as he described the incident, helped raise US$150,000 in donations in less than 24 hours for Oxford's Wildlife Conservation Research Unit, which had long been "responsible for tracking Cecil's activity and location".

[75] U.S. Congresswoman Betty McCollum of Minnesota, co-chair of the United States Congressional International Conservation Caucus, suggested an investigation of Palmer and the killing.

[77] On 30 July 2015, the United Nations General Assembly in New York adopted a non-binding resolution to strengthen the efforts to address illicit wildlife poaching and trafficking.

Said Braun: "Like most people in the world we are outraged at what happened to this poor lion;"[78] Issoze-Ngondet added that Cecil's killing was "a matter of deep concern for all countries in Africa".

[44] On 29 July 2015, Bronkhorst appeared in court at Victoria Falls and pleaded not guilty to a charge of "failing to prevent an unlawful hunt".

[82] On 11 November 2016, the High Court in the city of Bulawayo threw out the charges against Bronkhorst, agreeing with the defense that it could not have been a crime under the country's wildlife laws if Palmer had a legal permit to hunt.

[94][95] Initially, both the University of Oxford study[21] and Johnny Rodrigues, head of the Zimbabwe Conservation Task Force, indicated that they believed Cecil's six cubs could be killed by the new dominant male in the pride.

[11] According to Wayne Pacelle, president of the Humane Society of the United States and who petitioned for the new listing, Cecil had "changed the atmospherics on the issue of trophy hunting around the world," adding "I think it gave less wiggle room to regulators.

[11][103] The investigative journalist George Knapp noted Cecil's case on the approach of the incident's one-year anniversary during an annual animal-welfare broadcast concerning issues, the development of law, animal cruelty, and remediation efforts in June 2016.

The 2016 broadcast covered various issues, including horses and trophy hunting, noting Cecil and the effect the incident was still causing at the date of the show.

Byron du Preez, project leader at the Bubye Valley Conservancy, believes the effect does not exist, saying, "Hunters are not coming because there is a massive recession [in the U.S.].

[107] Andrew Loveridge, in his book Lion Hearted: The Life and Death of Cecil & the Future of Africa's Iconic Cats (2018), suggests that the hunters allowed Cecil to suffer for more than 10 hours, without hastening his death with a firearm, possibly to allow Palmer to submit the game to a hunting record book as an archery-hunted animal.

[108] In 2021, National Geographic Channels aired the documentary produced by wildlife filmmaker Peter Lamberti from Lion Mountain Media, Cecil: The Legacy of a King.