Donald Freese, 21, was convicted in January of attacking Alhaji Kargbo, a black man, outside the Hooksett Market Basket, the Concord (N.H.) Monitor reported.
During the attack, Freese repeatedly called Kargbo a racial slur.
In opening statements during Freese's January trial at Merrimack County Superior Court, prosecutor Wayne Coull said that less than 50 years ago, King "stood in front of the Lincoln Memorial and spoke of his dream of a world without racial prejudice, without racial bias, without racial hatred."
"Dr. King would be sad if he were alive and here today because what I'm going to have to talk to you about and what the witnesses are going to be telling you about is racial hatred, bias and animus in its most ugly form," Coull told the jury.
Freese's lawyer, Ted Barnes, sought a mistrial, arguing that Freese was not motivated by racism, and that the racial slur he used during the attack was a convenient insult.
Nonetheless, Freese was found guilty and sentenced to up to 12 years in prison.
Now, Freese is seeking to appeal his conviction, alleging that Coull took advantage of the fact that his first trial took place just before the Martin Luther King holiday.
Barnes has raised concern with Coull's statements about King, as well as witnesses being questioned about their personal reaction to Freese's use of the racial slur.
The appeal will be heard by the New Hampshire Supreme Court.