Walter Wadmore worked on tour and at the Opera Comique under D'Oyly Carte management in 1878. With the touring Comedy Opera Company, he appeared for a time as the Defendant in Trial by Jury (March-April), then came to the Opera Comique where he deputized briefly for George Power as Alexis in The Sorcerer and the Defendant in Trial (April). When Power resumed Alexis later that month, Wadmore remained as the Defendant. After The Sorcerer and Trial closed in May 1878, Wadmore appears to have returned to the touring Company, appearing as Old Miggs in J. H. Ryley's curtain-raiser Congenial Souls (November-December 1878).

Wadmore was residing in London in 1881, and, though he gave his occupation as "professional singer (musician)" for that year's census, no roles in opera or musical theatre after 1878 have come to light. Perhaps he was primarily a concert artist.