[5] While still a boy he later took part in amateur theatricals, with his mother's encouragement: the actor Walter Lacy recalled seeing him play the title role in Richard III in a juvenile performance at Mile End Assembly Rooms.

[7] Although his apprenticeship was not fully served out, due to the early retirement of his master, Robson was skilled enough to set up in business for himself, and according to one source was 'a seal engraver of considerable talent'.

[8] According to one source[7] Robson's first professional engagement was late in 1842 at Whitstable: another suggests he may have begun at a London tavern-cum-concert hall, the Bower Saloon,[11] where he began developing his repertoire as a comic singer.

[14] After some eighteen months in the provinces, in February 1844 he won an engagement[15] at the Grecian Saloon, City Road, London, where he began his climb to success.

[17] The engagement at the Grecian gave Robson varied experience, but though the venue presented plays, its theatrical standing (and that of its performers) was tainted by its downmarket past as a saloon.

[24] On 25 April, Robson took the lead in a burlesque version of Macbeth, a freewheeling adaptation that poked fun at the solemn and scholarly productions of Shakespeare offered by the likes of Charles Kean, while also including as many popular American minstrel songs as it could.

[25] Reviewers were impressed, commenting that Robson's Macbeth was more than a simple caricature: "His peculiarity is that he really seems to be aware of the tragic foundation which lies at the bottom of the grotesque superstructure".

[31] Robson's talent for burlesque came to the fore again in Shylock, or The Merchant of Venice Preserv'd in which, playing the title role, he again produced the unsettling effect of veering from comedy to tragedy and back within a single speech.

[33] Dickens, who saw both, preferred Robson – not for his comedy, but because he found him more moving in the tragic passages, writing: "[T]he extraordinary power of his performance ... points to the badness of Ristori's acting in a singular way by bringing out what she might do, and does not.

[38] Other roles in which Robson excelled included the sinister Desmarets in Plot and Passion,(1853)[39] the malevolent spirit Gam-Bogie in The Yellow Dwarf(1854)[40][41] and deformed Prince Richcraft in a fairy extravaganza, The Discreet Princess(1855).

[42] Henry James, who as a child saw him in the latter role, never forgot it: "I still see Robson slide across the stage, in one sidelong wriggle, as the small black sinister Prince Richcraft of the Fairy Tale; everything he did at once very dreadful and very droll, thoroughly true and yet nonetheless macabre..."[43] Thackeray, who saw him in The Yellow Dwarf, was astonished to find himself at one point almost in tears at a burlesque.

[49] His admirers included not only literary men such as Dickens and Thackeray but also royalty: Queen Victoria and Prince Albert were keen fans, inviting him to Windsor for many royal command performances and asking for The Yellow Dwarf in particular five times.

[59] But the family seems not to have been entirely estranged: young Frederick later recalled visiting his grandmother while his father was in Ireland,[60] and once he achieved success at the Olympic Robson brought both children, although not his wife, to live with him.

Very shortly after this however Mrs Manly departed and Rosetta Robson returned, as a result of efforts by the eldest son, Frederick, to reconcile his parents.

In 1879 she declared that he was her legitimate son by her husband, stating that Robson had visited her at times during their separation and on one of these occasions Edwin was conceived, although his birth had not been registered.