Stephane Charbonnier, editor of the French satirical magazine Charlie Hebdo, was among four cartoonists killed in the Paris massacre which left 12 people dead in total.
Charbonnier, known as "Charb", was 47. He had received death threats in the past and had been under police protection.
Reports say he was in an editorial meeting with the others when two masked gunmen burst in and opened fire with Kalashnikov assault rifles.
The gunmen reportedly shouted "Allahu akbar!" (God is great).
The left-wing magazine's famous cartoonists went by nicknames - the others who died were called Cabu, Tignous and Wolinski.
Charb had strongly defended Charlie Hebdo's cartoons featuring the Prophet Muhammad.
"Muhammad isn't sacred to me,'' he told the Associated Press in 2012, after the magazine's offices had been fire-bombed.
"I don't blame Muslims for not laughing at our drawings. I live under French law. I don't live under Koranic law."
In 2007 Charlie Hebdo also defended itself in court over cartoons of the Prophet Muhammad, reprinted in the magazine, which had angered Muslims.
But Charlie Hebdo's anti-establishment satire was wide-ranging - it included poking fun at the far right, and aspects of Catholicism and Judaism.
The Belgian newspaper La Libre Belgique says a cartoon by Charb this week was hauntingly prophetic.
It was headlined "Still no attacks in France" and showed an Islamist militant with the speech bubbles: "Wait! We still have until the end of January to present our wishes" - a satirical play on new year wishes.
He was the weekly magazine's most recent editor, having taken the reins in 2012.
Charlie Hebdo was launched in 1969 but folded in 1981. However it was resurrected in 1992. Its circulation was not very big.
Its offices were destroyed in a petrol bomb attack in November 2011, a day after it named the Prophet Muhammad as "editor-in-chief" for its next issue.
In a BBC interview Charbonnier said that incident was an attack against freedom itself and an act by "idiot extremists" not representative of France's Muslim population.
He said the attack showed that Charlie Hebdo was right to defy Islamists and "make their lives difficult, as much as they do ours".
His regular illustrations for the magazine were titled "Charb doesn't like people".
Other cartoonists killed
The other three cartoonists killed were: Jean Cabut, known across France as Cabu; Georges Wolinski; and Bernard Verlhac, better known as Tignous.
Also shot dead was popular economist Bernard Maris, 68, not a cartoonist but well-known for his Charlie Hebdo editorials and national radio commentaries.
Cabu: Jean Cabut, 76
Cabu traced the times he lived in for nearly six decades, sparing no-one and nothing: not presidents, not the military, not religion. In that, he carried on a tradition of French pamphleteers.
Cabu's most enduring creation was the "Beaufs", caricaturing the worst of French complainers, racists and jingoists.
But it was cartoons he did of the Prophet Mohammed for Charlie Hebdo, among his most caustic work, that brought ceaseless death threats upon him and the newspaper's staff.
"Cartoonists live on stupidities and that will never be turned back," he once said.
Wolinski: Georges Wolinski, 80
Wolinski was a legend in French cartooning, with work stretching back to well before Charlie Hebdo's beginning in 1970.
Born in Tunisia in 1934 to a Polish father murdered when he was just two years old, and to an Italian mother from Tuscany, Georgie, as he was called by his grandmother, discovered comic books from US soldiers deployed to North Africa.
Arriving in Paris at the end of World War II, he started illustrating his high school newspaper and then moved on in 1961 to a publication called Hara Kiri. When that paper was ordered closed by officials, he moved on with its staff to start Charlie Hebdo.
"We used cartoons to talk about the times we lived in, about society, about women," he said.
In the 1980s and 1990s, Wolinski struck out on his own to work for several of France's leftist mainstream newspapers and magazines. In 1992 he returned to Charlie Hebdo while also publishing his own comic book work separately.
Tignous: Bernard Verlhac, 57
Less well-known than the others, but still very much appreciated in the industry for his corrosive touch and energy, Verlhac had been a cartoonist for the French press since the 1980s. He worked for several other outlets at the same time as for Charlie Hebdo.
"A newspaper cartoon is extremely difficult to get right because you have to get everything into just one frame. It's the opposite of comics," he once said.