[1] His siblings included William Lassiter, who was a career United States Army officer and attained the rank of major general.

Lassiter was appointed by President Grover Cleveland to be United States attorney for the eastern district of Virginia in 1893 and served until 1896, when he resigned.

Lassiter was elected as a Democrat to the Fifty-sixth Congress to fill the vacancy caused by the death of Sydney P. Epes.

Lassiter was elected to the Sixtieth and Sixty-first Congresses and served from March 4, 1907, until his death in Petersburg, Virginia, October 31, 1909.

His family papers are held by the Special Collections Research Center at the College of William & Mary.