While occupied in business in Cheapside with a shawl manufacturer named Warwick, he took part in amateur entertainments, appearing at the Soho Theatre in Othello.
[1] At the Theatre Royal, Drury Lane, Montgomery replaced Samuel Phelps 6 March 1865 in Cymbeline, as Leonatus Posthumus to the Imogen of Helen Faucit, and in April, for the benefit of James Robertson Anderson, who acted Mark Antony, he played Cassius in Julius Caesar.
'In July he undertook a temporary management of the Haymarket, at where, with Madge Robertson (Mrs. Kendal) as Ophelia, he appeared on the 29th as Hamlet, a moderate success.
He also played Claude Melnotte in The Lady of Lyons, King John, Shylock, and Iago to the Othello of Ira Aldridge; and was the original Lorenzo in Fra Angelo, a tragedy in blank verse, by William Clark Russell, the not very successful experiment closing on 9 November.
[1] Montgomery made reputation in America and Australia, being well received as Louis XI and Sir Giles Overreach in A New Way to Pay Old Debts.