Wilhelm Liebknecht, the son of Katharina Elisabeth Henrietta and Ludwig Christian Liebknecht, was born in Gießen on 29th March, 1826. His parents died when he was a child and he was raised by relatives. He went to a local school before studying philology, theology and philosophy in Berlin and Marburg.
In 1847 he became a teacher of a progressive school in Zurich. Later that year a civil war erupted in Switzerland. He sent eyewitness reports to the German newspaper, The Mannheimer Abendzeitung.
Liebknecht now decided to become a journalist. He went to Paris in 1848 to report on the uprising. He then moved onto Germany but was arrested in Baden and charged with treason. However, a mob secured his release. He escaped to Switzerland and became a leading member of the Worker's Association in Geneva. Now a committed revolutionary, Liebknecht activities eventually got him banished from the country.
In 1850 Liebknecht moved to London, where he associated with other socialists such as Karl Marx, Friedrich Engels, George Julian Harney, Ernest Jones and Robert Owen. Liebknecht, Marx and Engels became members of the Communist League. He later recalled: "During the thirteen years I spent in England I learnt to know the English workers and to love them. Far from looking askant at the foreigner, they have, on the contrary, a considerate sympathy with him, which seemed to me not infrequently excessive... The great heart of the English workers has never failed. Wherever there has been fighting for the cause of labour and humanity, there were the true, sincere, and, where need was, the practical sympathies of the English workers."
After the amnesty for the participants in the revolution of 1848, Liebknecht moved back to Germany and joined the General German Workers' Association (ADAV), that had been formed by Ferdinand Lassalle. Liebknecht moved to Leipzig where he met August Bebel. The two men became close friends. Bebel later recalled: "Liebknecht’s genuine fighter’s nature was keyed up by an impregnable optimism, without which no great aim can be accomplished. No blow that struck him, personally or the party, could rob him for a minute of his courage or of his composure. Nothing took him unawares; he always knew a way out. Against the attacks of his antagonists his watchword was: Meet one rascal by one and a half. He was harsh and ruthless against our opponents, but always a good comrade to his friends and associates, ever trying to smooth over existing difficulties."
Over the next few years the worked together in an effort to spread the ideas of Karl Marx. In 1868 he won a seat in the Reichstag. In his book, On The Political Position of Social-Democracy (1869), he explained: "The question as to what position Social-Democracy should occupy in the political fight, can be answered easily and confidently if we clearly understand that socialism and democracy are inseparable. Socialism and democracy are not identical, but they are simply different expressions of the same principle; they belong together, supplement each other, and one can never be incompatible with the other. Socialism without democracy is pseudo-socialism, just as democracy without socialism is pseudo-democracy. The democratic state is the only feasible form for a society organized on a socialist basis.... We call ourselves Social-Democrats, because we have understood that democracy and socialism are inseparable. Our programme is implied in this name. But a programme is not designed to be given merely lip-service and to be repudiated in action. It should be the standard which determines our conduct."
In 1869 Liebknecht and August Bebel formed the Social Democratic Workers' Party of Germany (SDAP) together. They also established a newspaper, Der Volksstaat. In 1870 the two men used the newspaper to promote the idea that Otto von Bismarck had provoked France into war and called on workers from both countries to unite in overthrowing the ruling class. As a result, Bebel and Liebknecht were arrested and charged with high treason. In 1872, both men were convicted and sentenced to two years in the Königstein Fortress.
On his release in 1874 Liebknecht was once again elected to the Reichstag. The following year he helped the SDAP merge with the General German Workers' Association (ADAV), an organisation led by Ferdinand Lassalle, to form the Social Democratic Party (SDP). In the 1877 General Election in Germany the SDP won 12 seats. This worried Otto von Bismarck, and in 1878 he introduced an anti-socialist law which banned Social Democratic Party meetings and publications.
Paul Frölich was a member of SDP who was critical of Liebknecht's leadership. He argued: "In the German social-democratic movement the policy of repudiating the use of violence in the political struggle had become practically a dogma. Wilhelm Liebknecht, whose tongue often enough ran ahead of his ideas, had once declared that violence only served reactionary ends - a remark which was repeated with gusto on every possible occasion."
After the anti-socialist law ceased to operate in 1890, the SDP grew rapidly. However, Liebknecht and August Bebel had problems with divisions in the party. Eduard Bernstein, a member of the SDP, who had been living in London, became convinced that the best way to obtain socialism in an industrialized country was through trade union activity and parliamentary politics. He published a series of articles where he argued that the predictions made by Karl Marx about the development of capitalism had not come true. He pointed out that the real wages of workers had risen and the polarization of classes between an oppressed proletariat and capitalist, had not materialized. Nor had capital become concentrated in fewer hands. Bernstein's revisionist views appeared in his extremely influential book Evolutionary Socialism (1899). His analysis of modern capitalism undermined the claims that Marxism was a science and upset leading revolutionaries such as Vladimir Lenin and Leon Trotsky.
Liebknecht also had trouble from the left of the SDP. He came into conflict with Rosa Luxemburg over her militant articles in Vorwarts. Her biographer, Paul Frölich, has pointed out in his book, Rosa Luxemburg: Her Life and Work (1940): "When Luxemburg published her articles on the Oriental question, even old Wilhelm Liebknecht set upon her with a letter which failed to refute any of her arguments, but which let fly at her a whole quiver of choice invectives, going so far as to make the scarcely veiled accusation that she had been bought by the Russian Okhrana - an action which, somewhat later, the old man admitted to be wrong and regretted."
Wilhelm Liebknecht died in Charlottenburg on 7th August 1900.