Luigi Rinaldo Legnani was one of the greatest Italian guitarists of the romantic period. His predecessors had established the audiences for the guitar and made possible his career as a touring performer; on the other hand, they had also raised the technical standards and the expectations of these audiences. Legnani’s virtuosity was often compared with that of his friend Paganini, who was himself a competent guitarist and who once stated that he considered Legnani "first" among guitarists. One Spanish critic wrote of Legnani’s "remarkable agility of execution," of his "tone of infinite depth and rare singing beauty," and celebrated his cantabile on the bass strings. Nothing less was expected from a concert artist in the days of Chopin and Liszt.

Legnani was born in Ferrara in 1790, but his family moved to Ravenna when he was eight; that ancient city served as his home base throughout his life, and it was there that he died in 1877. Legnani studied music and the guitar in Ravenna, performed with the local opera company, and made his début as a guitarist in Milan in 1819. He was an instant success, and his concert tours expanded to include all the western capitals, from Madrid to St Petersburg. For the next thirty years, Legnani became part of the European musical mainstream. He collaborated with the Viennese pianist and publisher Max Joseph Leidesdorf in several compositions, and the arias of his good friend Rossini formed the bases for many of his fantasies and variations. Legnani not only performed with the great violinist Paganini, but he also stayed with him at his estate near Parma during one of the latter’s extended convalescences, and assisted him in preparing a number of works for publication. Like many guitarists, Legnani became fascinated with guitar construction and sought ways to improve his instrument. He collaborated with the Viennese luthiers Georg Ries and Johann Anton Staufer, both the whom created "Legnani model" guitars; in later life (after 1850), Legnani retired to Ravenna, where he himself became a renowned builder of violins and guitars.

Legnani was trained as a string player while very young but dedicated himself to guitar and voice. His debut was in Ravenna in 1807; in the 1820s he performed as a tenor in operas by Rossini, Pacini, and Donizetti. His career as a guitarist began with a concert in Milan in 1819; his 1822 concerts in Vienna were a great success, and he was hailed as a star when he returned there in 1833 and 1839.

He is perhaps best known for his 36 Caprices for the guitar, which cover all the major and minor keys, and which were probably inspired by Paganini's 24 Caprices for the violin. He and Paganini were friends from the 1830s; while it was once thought that he and Paganini performed together in public, this is no longer accepted. After the 1850s Legnani retired from active performance and became an instrument maker, concentrating on guitars and violins. The "Legnani model" guitar was popular in Central Europe through the middle of the nineteenth century.

Legnani composed some 250 works, which were published in his lifetime throughout many of the major publishing houses in Europe. He died in Ravenna.