Rostand's name is indissolubly linked with that of his most popular and enduring play, Cyrano de Bergerac. First performed in Paris in 1897, with the famous actor Constant Coquelin playing the lead, Cyrano made a great impression in France and all over Europe and the United States. The plot revolves around the emotional problems of Cyrano, who, despite his many gifts, feels that no woman can ever love him because he has an enormous nose. The connection between the Cyrano of the play and the 17th-century nobleman and writer of the same name is purely nominal. But Rostand's stirring and colourful historical play, with its dazzling versification, skillful blend of comedy and pathos, and fast-moving plot, provided welcome relief from the grim dramas of the naturalists and Symbolists.

Rostand wrote a good deal for the theatre, but the only other play of his that is still much remembered is L'Aiglon (1900). This highly emotional patriotic tragedy in six acts centres on the Duke of Reichstadt, who never ruled but died of tuberculosis as a virtual prisoner in Austria. Rostand always took pains to write fine parts for his stars, and L'Aiglon afforded Sarah Bernhardt one of her greatest triumphs.

Rostand's son Jean Rostand (1894–1977) was a noted biologist, moralist, and writer.