Outside of his law practice, Rhett actively participated in the phosphate industry, constructing factories and assuming leadership roles until ownership consolidated into the Virginia-Carolina Chemical Company.

[1][2] By his second term as major, Rhett had served on the Board of Directors for at least 25 separate Charleston companies and had been president of eight building and loan organizations.

[3] During Rhett’s tenure as mayor (1903-1911), he was responsible for the establishment of the Board of Public Works, the construction of new police and fire stations,[1] and the expansion of the city through landfill along the southwest edge of the peninsula.

[citation needed] Rhett also played an instrumental role in the establishment of Roper Hospital, Union Station, and Julian Mitchell Elementary School.

[4] Rhett continued in political service, later becoming the president of the Chamber of Commerce of the United States in 1916–1918 and serving as the chairman of the South Carolina Highway Commission in 1920–1926.