Bemis was one of the most esteemed lawyers in Boston during the 1850s and developed a profitable law practice while being involved in many famous legal proceedings.

Bemis was a crusader for reform of the penal code in Massachusetts, especially laws that allowed a defendant's previous convictions to extend his current sentence.

[2] In 1843 he was involved with the case of Abner Rodgers, an inmate at the Massachusetts State Penitentiary accused of killing the warden of that prison.

The author Robert Sullivan, in his book on the case, characterized the published transcripts from the Webster trial were considered to be heavily edited and "slanted" to justify the execution of Dr.

During this time in Europe, he focused on the study of public law; he published many pamphlets about neutrality in response to British positions on these topics.