Although there is no record of his having had any further education, Lewis Morris began his career as an estate-surveyor, and was employed by the Meyrick family of Bodorgan.
Morris put his idea for a survey to the Admiralty, but they showed little interest and he was obliged to undertake the work at his own expense.
While this work had a major impact on the safety of shipping around the Welsh coast at the time; Morris's contribution to British cartography was for many years eclipsed by his other achievements.
In his spare time, Morris began prospecting for lead, and during the 1750s he was in constant dispute with his employers and was prosecuted and lost his job as collector of tolls at Aberdyfi.
He visited London several times in order to contest court cases relating to his industrial activities; whilst there, he assisted his brother Richard in setting up the Cymmrodorion Society.