At the age of twenty Penley made his stage debut in 1871 at the Court Theatre, London as Tim, the porter, in a revival of John Maddison Morton's farce, "My Wife's Second Floor". The following year he played in T. F. Plowman's burlesque "Zampa" at the Court, and performed at the Holborn Theatre in Hervé's operetta "Doctor Faust". Among the cast of "Zampa" was Selina Dolaro, whose company Penley joined under the management of Richard D'Oyly Carte at the Royalty Theatre in London and on tour, in 1875. He played one of the two notaries in Offenbach's "La Périchole", and was in the chorus of its companion piece, Gilbert and Sullivan's "Trial by Jury". In November of that year he was promoted to the role of the Foreman of the Jury in the latter work when it returned to the Royalty. He continued in the part when the opera played on another tour and in London, at the Opera Comique and the Royal Strand Theatre in 1876–77. Penley was considered to be an important addition in the small role, with his malleable comic features.