[2] On his father's death in 1836, Wyld became the sole owner of the thriving family mapmaking business based in Charing Cross.

His maps, which covered regions as diverse as London and the gold fields of California, were regarded highly, and Wyld himself had an excellent reputation as a mapmaker; he was elected as a fellow of the Royal Geographical Society in 1839, and he was appointed Geographer to Queen Victoria and Prince Albert (as had been his father before him).

[2] He had an opportunistic approach to the business and was a prolific publisher of maps and guides (so much so that Punch claimed that if a country were discovered in the interior of the Earth Wyld would produce a map of it "as soon as it is discovered, if not before"[3]), but his projects were not always successful; although he profited from the "Railway Mania" of the later 1830s, he became entangled in a number of court cases with unsuccessful railway companies as a result,[2] and he overreached himself by printing maps and guides of the London rail network which included stations and connections that were planned but subsequently not built.

[2] He had an account at the Royal British Bank, which collapsed in 1856, wiping out the savings of many of the depositors, but the extent of his losses is not recorded.

Wyld was the chairman of the depositors committee which managed to negotiate a favourable return of 15 shillings in the pound from the shareholders.