[1] Soon after, Allen moved to Portland, Maine and studied law, working as an apprentice to Samuel Fessenden, a local abolitionist and attorney.

"[3] Allen was granted his license to practice law in Maine on July 3, 1844, becoming the nation's first African American lawyer.

Allen's client, the defendant, lost, although the jury awarded lower damages than the plaintiff had requested.

Racial prejudice made it difficult for him to earn a living; in 1845, he wrote a letter to John Jay Jr. (the grandson of the country's first Chief Justice) discussing the difficulty of finding clients in Boston and wondering whether he would do better in New York City, with its larger African American population.

[1] After passing a rigorous qualifying exam for Justice of the Peace for Middlesex County, Massachusetts in 1847, Allen became the second African American in the United States to hold a judicial position,[5][6] following only Wentworth Cheswell (who in 1805 was elected as the Justice of the Peace for Rockingham County, New Hampshire), despite not being considered a full U.S. citizen under the Constitution at the time (although see the remarks about state citizenship in the above section as well as the holdings about Maine in Dred Scott).

[1] Allen moved to Charleston, South Carolina, following the Civil War and opened a law office with two other African American attorneys, William Whipper and Robert Elliott.

[1] The state legislature in 1873 elected Allen (choosing him instead of Whipper) to be a judge of Charleston County Criminal Court.