Dee's dismissal was effective on Wednesday. The Alabama-based non-profit activist group is known for tracking civil rights and hate crimes in the United States.
SPLC Chairman Richard Cohen did not quote a particular reason for their dismissal but noted in a statement released on Thursday that the organization "is committed to ensuring that our employees' behavior reflects the mission of the organization and the values we hope to introduce "In the world."
"When one of us does not meet these standards, regardless of his or her role in organization, we take it seriously and must take appropriate action," he added.
Dees, 82, was also the former highest litigator. He founded in SPLC in 1
His biography has been removed from SPLC's website.
When asked about his termination, Dee told CNN that it was not his decision to leave SPLC.
"It's a very nice group. I've spent 50 years of my life in the middle. I wish them the very best," Dees said.
He would not elaborate on how he learned about his dismissal or reasoning behind it. He just said he "can let his life's work and reputation speak for himself".
Dees has said that most of the time he went to the center to call large donors. He is now looking forward to spending time with his grandchildren.
As SPLC's chief advisor, Dee began to use judgments in the early 1980s to secure money loss against hate groups. The courts then seized the assets of the groups.
In 1981, Dee successfully raised the Ku Klux Klan and won a $ 7 million damn dam for Michael Donald, a black lynch victim in Alabama. The verdict knocked the United Clan of America, who had to sell his national headquarters to help pay it.