He began as a reporter and polemicist in the Moroccan weekly La Vie Economique in 1996. After briefly serving as communication advisor for a cabinet member, he was editor in chief of Téléplus magazine in 1999. After the passing of King Hassan II, he was the correspondent in Morocco for Jeune Afrique magazine. In October 2001, he founded TelQuel, a weekly news magazine of which he became the publisher and editor. Under the editorial line “Morocco As It Is”, TelQuel covers monarchy, politics, business and culture and advocates democracy, secularism and individual freedoms. Its independent, liberal stand made it since its inception a resolute critic of the Makhzen (autocratic monarchic system) as much as of the Islamists. Both strongly attacked it in return. In 2005, TelQuel became the #1 weekly in Morocco. In 2006, Benchemsi founded Nishan, the Arabic version of TelQuel, defending the same values and editorial line. In 2008, Nishan became the #1 Arabic weekly in Morocco. In October 2010, after 4 years of confrontation with the authorities (see section “legal record”) Benchemsi was forcibly driven to close Nishan, which bankrupted as a consequence of a longstanding advertising boycott campaign, orchestrated by companies close to the royal palace. In December 2010, he quit TelQuel (in order to save it from following Nishan’s path, observers said) and left Morocco to the United States. Since January 2011, he is a political science researcher in Stanford University and an op-ed writer for international outlets such as Le Monde, Time and the Guardian.
TelQuel’s editorial line got Benchemsi in trouble with the Moroccan authorities, which repeatedly prosecuted him in what Reporters Without Borders rebuked as “judicial harassment”. In December 2006, after a cover story titled “How Moroccans Joke about Religion, Sex and Politics”, Nishan was banned by decision of Prime ministerDriss Jettou. Whereas Benchemsi and Nishan staffers received death threats as much as support letters from all over the world, the then editor-in-chief and the author of the controversial article were sued by the government for “damaging Islam”. They were condemned to 3 years suspended prison. In August 2007, Benchemsi was interrogated during 2 days in custody about one of his editorials. 100,000 copies of TelQuel and Nishan were seized and destroyed by police forces. Benchemsi was sued for “disrespecting the King”, which in Morocco is worthy of 5 years in prison. One year later, the trial was adjourned without verdict. In August 2009, 100,000 copies of TelQuel and Nishan were seized again and destroyed by the police, this time because it featured an opinion poll on King Mohammed’s public record, jointly conducted with the French daily Le Monde. “The King is above polling,” said the government spokesman before writing a violent op-ed against the two weeklies. In 2010, the same official, who is also Minister of Information, signed a vehement "open letter to Ahmed Benchemsi"
In 1996, Benchemsi received in Casablanca, at the age of 22, the “investigative story award,” granted by Morocco’s journalists union. In 2005, he received in Brussels the Lorenzo Natali prize, granted by the European commission to "journalists who contribute to the cause of democracy”. In 2007, he received in Beirut the Samir Kassir Award  for Freedom of the Press, granted by the European Union. Under Benchemsi's supervision, many TelQuel and Nishan journalists received international awards, notably the RFI-Reporters without borders  prize and the Press Now prize. Benchemsi completed fellowships in Newsweek and the Los Angeles Times. He Also gave conferences in the Middle-East, Europe, the United States and India on freedom of speech in Morocco, and on Islam and Secularism.