He was admitted to the bar and commenced the practice of law in Snow Hill, Maryland.

In 1932, he was elected chairman of the board of Commercial National Bank of Snow Hill.

[3] In 1962, while he was running for re-election, charges were brought against him regarding the receipt of illegal gratuities in Congress.

He was convicted of conspiracy and conflict of interest in 1968, served three and a half months of a six-month sentence in jail, and paid a $5,000 fine.

[2][5] After Congress, Johnson resumed the practice of law and lived in Berlin, Maryland until his death in a car crash in Seaford, Delaware in 1988.