in 1783 rigby became a member of the corporation of guardians of norwich, and promoted the economical administration of the poor laws. meeting with much opposition, he resigned in the following year. he became alderman in 1802 in a very tight contest for the north ward, sheriff in 1803, and mayor of norwich in 1805, presiding over a meeting addressing the issue of smallpox in the city. rigby is said to have made known the flying shuttle to norwich manufacturers, and to have introduced vaccination.