For nearly half a century as publisher, politician, journalist and writer, Jean-Jacques Servan-Schreiber, who has died aged 82 of complications from bronchitis, helped set the public agenda in France. He co-founded the influential magazine L'Express, and wrote books on the torture he saw as a French soldier in Algeria and the threat that expanding American investment posed to the European economy.
The young Servan-Schreiber grew up in Paris, surrounded by politicians and political commentators. His grandfather had been a close aide to the German chancellor Bismarck, and had resigned over the 1870 war between Prussia and France. He moved to France, where the eldest of his three sons founded the economic and business daily Les Echos; the youngest son, Jean-Jacques' father, wrote for the weekly L'Illustration. Politicians - notably the future premier Paul Reynaud and the victim of anti-semitism Georges Mandel - and journalists frequented the Servan-Schreiber home, and Jean-Jacques' earliest memories were of discussions about Hitler and the inadequacies of the third republic.
The Nazi occupation of 1940 led to Servan-Schreiber being sent to the Lycée Champollion in Grenoble, where he prepared for the competitive entrance exam for the Ecole Polytechnique. He was successful in 1943, but decided to join General de Gaulle's Free French forces in north Africa. Having arrived in Morocco, he was sent to train as a pilot in the US, returning to Europe only in the closing months of the war. After training as an engineer at the Ecole Polytechnique, he went to Brazil for his first job.
Servan-Schreiber never denied he had a privileged early life. But once back in France, he had two particularly lucky encounters. The first was with Hubert-Beuve-Méry, the founder and director of Le Monde, who took him on to write articles and editorials. These, in turn, led to him meeting leading political figures of the time, notably Jean Monnet, the architect of European unity, and the German chancellor Konrad Adenauer. They also brought about the second fortunate encounter, when the editor of Paris-Normande arranged for Servan-Schreiber to meet the radical deputy Pierre Mendès France.
Servan-Schreiber became convinced that this was the man who could save France, and on May 16 1953 the first edition of L'Express carried an interview with him. The magazine's aim was to oppose colonial wars, notably in Indo-China, and modernise France both economically and socially. To accomplish this it was necessary to increase Mendès France's popularity. One way was to get him known as PMF, as Franklin Roosevelt had been known as FDR and as Servan-Schreiber was known as JJSS. It was not until June 18 1954 that Mendès France became prime minister. He won a vote of confidence from the national assembly because he undertook to make peace in Indo-China within a month, or resign. This tactic was supposedly suggested to him by Servan-Schreiber, who went with the new premier to Geneva for peace negotiations.
After Indo-China, it was the war in Algeria that L'Express and Servan-Schreiber wanted to stop. By coincidence, in 1956 Servan-Schreiber himself was among the reservists called up to serve in the rebellious north African colony, where he became associated with those who denounced the torture being used by the French army. In 1957 he published his first book, Lieutenant en Algérie, which was hostile to the notion that Algeria was part of France and scathing about the French settlers.
L'Express continued to prosper, although an attempt to turn it into a daily newspaper during the mid-1950s had failed. But with the arrival of De Gaulle as president in 1958, the political atmosphere changed. Servan-Schreiber's opposition to the general cost him the support of some of the paper's collaborators, notably the writer François Mauriac, and as Gaullist power became established, it seemed that L'Express could not continue as a fighting political magazine. In 1964 it became a journal of information, and its weekly sales rose from 150,000 to 500,000 three years later.
Servan-Schreiber now turned his attention to the Gaullists' anti-Americanism. The result was his second book, Le Défi Américain (1967), in which he warned that the gap between the US and Europe was increasing in terms of technology, management and marketing. Unless France and her European partners united in a joint effort to compete, he prophesied disaster. The book, which showed admiration for American dynamism and was critical of Gaullism's narrow nationalism, sold 400,000 copies in France within three months, and its success encouraged its author's political ambitions.
Servan-Schreiber chose the Radical-Socialist party as his base, becoming its secretary-general in 1969 and president in 1971. His rejoicing at the downfall of De Gaulle kept him at the centre of public controversy, as did his 1970 manifesto Ciel et Terre, which sought to liberate France with a programme of decentralisation. He was elected deputy for Nancy at a byelection in June 1970, and following the death of President Georges Pompidou in April 1974 and the election of Valéry Giscard d'Estaing, he joined the government as minister for reform. He resigned over his opposition to France's continued nuclear tests, and although he was returned for Nancy in 1978, irregularities led to the election being annulled.
Since the previous year, when he sold L'Express to Sir James Goldsmith, Servan-Schreiber had been turning towards international politics, and in 1978 he became professor of strategic thinking and chairman of the Carnegie-Mellon University in Pittsburgh.
In the first volume of his memoirs, Passions (1991), he portrayed himself as being successful both with women and with politicians. This was true, but in his, at times, agitated life, he also made enemies. In 1984, when a group of historians and politicians met at the Sorbonne to discuss the work of Mendès France, his widow let it be known that she would leave immediately if Servan-Schreiber attended.
His first marriage ended in divorce. He is survived by his second wife and their four sons.
· Jean-Jacques Servan-Schreiber, publisher, politician and writer, born February 13 1924; died November 6 2006
· This obituary has been revised since the author's death in April 2005