Completing his MD degree in 1710, Meyer had practises in Schweinsberg, Blankenstein, and then Metz, but then moved to London and settled there in 1721.
The Royal College of Physicians admitted him as a licentiate on 19 March 1722 (giving his word and his bond, he was allowed to put off paying the £20 fee for that honour), on 12 January 1726 he became a fellow of the Royal Society, and finally in 1730 he was admitted to the freemasons' lodge of the Premier Grand Lodge of England at the Swan and Rummer, Finch Lane (serving as its grand steward in 1734).
By 1740 his professional income was said to be 4000 guineas a year, having established a successful practice (Sir William Browne attributed this to his offers of friendship and hospitality to young surgeons).
Becoming alienated from London's Jewish community in general and Sarmento and his allies in particular (explained in Schomberg's unpublished 1746 essay, Emunat omen, or ‘A physician's faith’, written in classical Hebrew, and involving his conversion to deism), he also got increasingly entangled in one expensive lawsuit after another.
He also rejected the Jewish community by – after 1742 – encouraging his sons to become Anglican Christians if that would aid them in the liberal professions for which he had had them educated.