The commedia dell'arte was a form of popular theatre that emphasized ensemble acting; its improvisations (improvisation) were set in a firm framework of masks and stock situations, and its plots were frequently borrowed from the classical literary tradition of the commedia erudita, or literary drama. Professional players who specialized in one role developed an unmatched comic acting technique, which contributed to the popularity of the itinerant commedia troupes that traveled throughout Europe. Despite contemporary depictions of scenarios and masks and descriptions of particular presentations, impressions today of what the commedia dell'arte was like are secondhand. The art is a lost one, its mood and style irrecoverable.

Many attempts have been made to find the form's origins in preclassical and classical mime and farce and to trace a continuity from the classical Atellan play to the commedia dell'arte's emergence in 16th-century Italy. Though merely speculative, these conjectures have revealed the existence of rustic regional dialect farces in Italy during the Middle Ages. Professional companies then arose; these recruited unorganized strolling players, acrobats, street entertainers, and a few better-educated adventurers, and they experimented with forms suited to popular taste: vernacular dialects (the commedia erudita was in Latin, or in an Italian not easily comprehensible to the general public), plenty of comic action, and recognizable characters derived from the exaggeration or parody of regional or stock fictional types. It was the actors who gave the commedia dell'arte its impulse and character, relying on their wits and capacity to create atmosphere and convey character with little scenery or costume.

The first date certainly associated with an Italian commedia dell'arte troupe is 1545. The most famous early company was the Gelosi (Gelosi, Compagnia dei), headed by Francesco Andreini (Andreini, Francesco) and his wife, Isabella (Andreini, Isabella); the Gelosi performed from 1568 to 1604. Of the same period were the Desiosi (Desiosi, Compagnia dei), formed in 1595, to which Tristano Martinelli (c. 1557–1630), the famous Arlecchino, belonged; the Comici Confidènti, active from 1574 to 1621; and the Uniti (Uniti, Compagnia degli), under Drusiano Martinelli and his wife, Angelica, a company first mentioned in 1574. Troupes of the 17th century included a second Confidènti troupe, directed by Flaminio Scala, and the Accesi (Accesi, Compagnia degli) and the Fedeli (Fedeli, Compagnia dei), to which Giovambattista Andreini, called Lelio, one of the great commedia dell'arte actors, belonged. The first mention of a company in France is in 1570–71. The Gelosi, summoned to Blois in 1577 by the king, later returned to Paris, and the Parisians embraced the Italian theatre, supporting resident Italian troupes who developed additional French characters. The Comédie-Italienne was formally established in France in 1653 and remained popular until Louis XIV expelled the Italian troupes in 1697. The Italian players were also popular in England, Spain, and Bavaria.

Each commedia dell'arte company had a stock of scenarios, commonplace books of soliloquies and witty exchanges, and about a dozen actors. Though there was some doubling of masks (roles), most players created their own masks or developed ones already established. This helped to keep a traditional continuity while allowing diversity. Thus, though many players are individually associated with parts—the elder Andreini is said to have created the Capitano, and Tiberio Fiorillo (Fiorillo, Tiberio) (1608–94) is said to have done the same for Scaramuccia (the French Scaramouche—for an understanding of the commedia dell'arte, the mask is more important than the player.

A typical scenario involved a young couple's love being thwarted by their parents. The scenario used symmetrical pairs of characters: two elderly men, two lovers, two zanni, a maidservant, a soldier, and extras. The lovers, who played unmasked, were scarcely true commedia dell'arte characters—their popularity depending on looks, grace, and fluency in an eloquent Tuscan dialect. The parents were clearly differentiated. Pantalone (Pantaloon) was a Venetian merchant: serious, rarely consciously comic, and prone to long tirades and good advice. Dottore Gratiano was, in origin, a Bolognese lawyer or doctor; gullible and lecherous, he spoke in a pedantic mixture of Italian and Latin.

Other characters began as stock masks and developed into well-known characters in the hands of the most talented players. The Capitano developed as a caricature of the Spanish braggart soldier, boasting of exploits abroad, running away from danger at home. He was turned into Scaramuccia (Scaramouche) by Tiberio Fiorillo, who, in Paris with his own troupe (1645–47), altered the captain's character to suit French taste. As Scaramouche, Fiorillo was notable for the subtlety and finesse of his miming. The zanni, who were often acrobats, or “tumblers,” had various names such as Panzanino, Buratino, Pedrolino (or Pierrot), Scapino, Fritellino, Trappolino, Brighella, and most notably, Arlecchino and Pulcinella (related to the English Punchinello (Punch), or Punch). Pulcinella, like Capitano, “outgrew” his mask and became a character in his own right, probably created by Silvio Fiorillo (died c. 1632), who had earlier created a famous Capitano, Mattamoros. Columbina (Columbine), a maidservant, was often paired in love matches with Arlecchino, Pedrolino, or the Capitano. With Harlequin she became a primary character in the English pantomime's harlequinade. The zanni had already been differentiated as comic rustic and witty fool. They were characterized by shrewdness and self-interest; much of their success depended on improvised action and topical jokes. Arlecchino ( Harlequin), one of the zanni, was created by Tristano Martinelli as the witty servant, nimble and gay; as a lover, he became capricious, often heartless. Pedrolino was his counterpart. Doltish yet honest, he was often the victim of his fellow comedians' pranks. As Pierrot, his winsome character carried over into later French pantomimes. The zanni used certain tricks of their trade: practical jokes (burle)—often the fool, thinking he had tricked the clown, had the tables turned on him by a rustic wit as clever, if not so nimble, as his own—and comic business (lazzi).

The decline of the commedia dell'arte was due to a variety of factors. The rich verbal humour of the regional dialects was lost on foreign audiences. Eventually the physical comedy came to dominate the performance, and, as the comic business became routine, it lost its vitality. As time went on, the actors stopped altering the characters, so that the roles became frozen and no longer reflected the conditions of real life, thus losing an important comic element. The efforts of such playwrights as Carlo Goldoni (Goldoni, Carlo) (1707–93) to reform Italian drama sealed the fate of the decaying commedia dell'arte. Goldoni borrowed from the older style to create a new, more realistic form of Italian comedy, and audiences greeted the new comedy with enthusiasm.

The commedia dell'arte's last traces entered into pantomime as introduced in England (1702) by John Weaver at Drury Lane Theatre and developed by John Rich at Lincoln's Inn Fields. It was taken from England to Copenhagen (1801), where, at the Tivoli Gardens, it still survives. Revivals, notably in the 1960s by a Neapolitan troupe led by Peppino de Filippo, by puppet companies in Prague, and by students and repertory players in Bristol and London, however carefully their masks copied contemporary illustrations, however witty their improvisation, could only approximate what the commedia dell'arte must have been.

A more important, if less obvious, legacy of the commedia dell'arte is its influence on other dramatic forms. Visiting commedia dell'arte troupes inspired national comedic drama in Germany, eastern Europe, and Spain. Other national dramatic forms absorbed the comic routines and plot devices of the commedia. Molière, who worked with Italian troupes in France, and Ben Jonson (Jonson, Ben) and William Shakespeare (Shakespeare, William) in England incorporated characters and devices from the commedia dell'arte in their written works. European puppet shows, the English harlequinade, French pantomime, and the cinematic slapstick of Charlie Chaplin (Chaplin, Charlie) and Buster Keaton (Keaton, Buster) all recall the glorious comic form that once prevailed. Despite the loss in Western theatre of its direct connections to commedia dell'arte's origins, the genre was sometimes used as a training component in physical and improvisational theatre at the beginning of the 21st century.