After moving to Laurel in 1936, he began his management of the Valliant Fertilizer Company, that would continue throughout his political career.

In his first attempt at public office, Carvel was elected lieutenant governor in 1944, defeating Republican Clayton Bunting, Sr.

He was opposed to capital punishment and was an early and persistent leader for civil rights legislation in a still politically conservative Delaware.

He was known as a liberal Democrat from conservative "lower Delaware," and never hesitated to promote causes of importance to him regardless of their impact on his political career or his fertilizer business.

The state office building at 820 North French Street, Wilmington is named for him, as is the University of Delaware Research and Education Center in Georgetown.

The cafeteria in North Laurel Elementary School is named the "Carvel Room", after him.