As a boy he had ambitions to be a sculptor's life but discovered his talent accidentally while appearing in some private theatricals. In 1841 he joined a travelling company that was going to Italy. The tour was a failure, and the company broke up; Fechter returned home and resumed the study of sculpture. At the same time he attended classes at the Conservatoire with the view of gaining admission to the Comédie Française. Late in 1844 he won the grand medal of the Académie des Beaux-Arts with a piece of sculpture, and made his debut at the Comédie Francaise as Seide in Voltaire's Mahomet and Valère in Molière's Tartuffe. He acquitted himself with credit; but, tired of the small parts he found himself condemned to play, returned again to his sculptor's studio in 1846.
In the same year he was invited to appear with a French company in Berlin, where he made his first decisive success as an actor. On his return to Paris in the following year he married the actress Eléonore Rabut (d. 1895). Previously he had appeared for some months in London, in a season of French classical plays given at the St James's Theatre. In Paris for the next ten years he fulfilled a series of successful engagements at various theatres, his chief triumph being his creation at the Vaudeville on February 2, 1852 of the part of Armand Duval in La Dame aux camilias. For nearly two years (1857-1858) Fechter was manager of the Odéon, where he produced Tartuffe and other classical plays.
Having received tempting offers to act in English at the Princess's Theatre, London, he made a diligent study of the English language, and appeared there on October 27, 1860 in an English version of Victor Hugo's Ruy Blas. This was followed by The Corsican Brothers and Don César de Bazan; and on March 20, 1861, he attempted Hamlet for the first time. The result was an extraordinary triumph, the play running for 115 nights. This was followed by Othello, in which he played alternately the Moor and Iago. In 1863 he became lessee of the Lyceum theatre, which he opened with The Duke's Motto; this was followed by The King's Butterfly, The Mountebank (in which his son Paul, a boy of seven, appeared), The Roadside Inn, The Master of Ravenswood, The Corsican Brothers (in the original French version, in which he had created the parts of Louis and Fabian dei Franchi) and The Lady of Lyons.
After this he appeared at the Adelphi Theatre (1868) as Obenreizer in No Thoroughfare, by Charles Dickens and Wilkie Collins, as Edmond Dantes in The Count of Monte Cristo, and as Count de Leyrac in Black and White, a play in which the actor himself collaborated with Wilkie Collins. In 1870 he visited the United States, where (with the exception of a visit to London in 1872) he remained till his death. His first appearance in New York was at Niblo's Garden. in the title role of Ruy Blas. He played in the United States between 1870 and 1876 in most of the parts in which he had won his chief triumphs in Britain. He made a few attempts at management, but was mostly unsuccessful, owing to his ungovernable temper. The last three years of his life were spent in seclusion on a farm which he had bought at Rockland Centre, near Quakertown, Pennsylvania, where he died. A bust of the actor by himself is in the Garrick Club, London.