I have been waiting for a question like this.
Short answer: he stopped being such a racist ass hat after having a near death experience.
Here is the long answer.
George Wallace is surprisingly hard to decipher. Yes he said some explicitly racist things like constantly saying the n-word and the aforementioned quote. However some have considered him as a populist who just says things to win political favors.
Case in point? Associate Justice Hugo Lafayette Black from Alabama (and personally my favorite despite his extreme flaw) When nominated by FDR in 1937, it was revealed that he had been a member of the Ku Klux Klan while as a Senator from Alabama. He profusely apologized to the American people by radio, but its now known that he joined the Klan for Political Gain. In 1958, he was having lunch with his clerks. One had the audacity to ask him "Mr. Justice, why did you join the Klan?" The room went silent. The Justice Black laughed and said "Why, son, if you wanted to be elected to the Senate in Alabama in the 1920s, you'd join the Klan too." Justice Black before becoming a senator was a well renowned attorney who in some cases defended Black people. He called out police brutality against suspects, especially African Americans but he couldn't use race to get his point across and used the common decency argument. Sometimes he used slurs to win his case either as prosecutor or defender, which he later regretted. It could have be seen as trying to sway the jury to his favor. However, he did constantly sided with African Americans when he was on the court. In fact in the original tallies for Brown v. Board of Education, which it was supposed to be 5-4, he was part of the majority to rule segregation unconstitutional. It late became unanimous under Chief Justice Earl Warren.
What does Justice Black have to do with George Wallace?
George Wallace did essentially the same thing as Black but Wallace was actually more racist.
Wallace originally ran for governor in 1958 against John Patterson, another Democrat. He was considered moderate by southern standards and had education and tax reform and was surprisingly moderate when it came to race so in a shocking manner, the NAACP actually supported Wallace. His opponent was supported by the KKK and as Black stated with becoming a U.S. Senator, the Klan holds the sway. Wallace lost in a landslide. After that he adopted a hardline segregationist stance so he would not be defeated again.
He won in 1963 with his famous speech and his segregationist holdings.
I would like to state for the record that I do not believe that he wasn't racist and didn't hold racist beliefs, which he did.
He ran for president in 1968 and mainly got southern states and was still a fire breathing racist prick.
Here is where it changes.
He runs for president in 1972 and is looking like he would be the main rival of more far left George McGovern, however a man named Arthur Bremer put that to a halt, and shot George Wallace multiple times, one hit his spine and permanently paralyzed him from the waist down, forcing him to be in a wheelchair for the rest of his life. In fact he almost died and it took many units of blood to keep him living.
It was after this near the end of this THIRD TERM (non consecutive) as Governor when he stated that he was a born again Christian and harbored regrets for his past actions. He ardently apologized for his mistakes to Civil Rights Leaders and asked the African Americans of Alabama for forgiveness for his mistakes. He even admitted that his famed Stand in the Schoolhouse Door stunt was wrong.
In 1983 in his final term, he won like you said with 90% of the Black Vote.
He appointed many black people to high places in his cabinet and still apologized for his actions until his death.
Could his apologies be fake? Probably. Could he still have been a racist asshole even after becoming a "born-again Christian?" Probably. We will most likely never know.
Do I think that he was a racist? Hell yes. Does he deserve criticism for his offensive comments? Absolutely. Should he ever 100% be off the hook for his past comments despite becoming a born again Christian? Hell no.
I will say this. I do think that he did harbor regret for his past comments and actions. I try and believe that he was sincere in his apologies to the African American community. He did show actions to back up his new found convictions. Hell he at least apologized for his actions. That alone is more than what most did. Orval Faubus never apologized for his handling of the Little Rock Nine, nor did Senator John Stennis of Mississippi on his voting record or Senator Strom Thurmond of South Carolina for Filibustering the Civil Rights Act of 1957.
The point is this, George Wallace was a EXTREMELY flawed man, especially with his fiery comments about African Americans. He should never be let off the hook for his comments. However, I will always acknowledge that at least he tried to make things right later in his life and saw the err of his ways. There is a chance that it was an act but I do believe in eventual forgiveness of past mistakes. In that aspect ALONE, I do have some respect for his determination to try to set things right with a community he famously and notoriously demonized.
I will say this one last time for the people who might think that I believe that George Wallace did nothing wrong.
GEORGE WALLACE WAS A RACIST PIECE OF SHIT AND SHOULD NOT BE TOTALLY FORGIVEN FOR HIS RACIST INCINDIARY ACTIONS DESPITE HIS CONSTANT APOLOGIES.
If you have any follow up questions, don't hesitate to ask. :)
edit: I will never let Justice Black off the the hook for being a Klansman, even though he is my favorite Supreme Court Justice.
edit 2: The section of (who was able to accomplish the impossible. He was able to get a Black man acquitted of murder by an all-white Klansman jury in Mobile, Alabama.) is inaccurate and has been changed. I will still keep the original language here.
I am extremely sorry.
I mixed up three different cases in one.
The first is a federal liquor bust where he prosecuted seventy two people with varying degrees of success and the jury was stacked with Klansmen. Most of convicted were democrats which was impressive.
The second is a murder trial where he did manage to get someone acquitted of murder by an all white jury with help from the Klan, however the defendant was a white Methodist priest that shot and killed another priest for performing an interracial marriage. Black used anti-Catholic language (which he later regretted) to try and get his client out and used interracial marriage as well and succeeded.
The third case actually involved a Black man. A former convict was injured in a mine and wanted reparations but the mine decided to go bankrupt and Black pressured for reparations, which the lower federal courts denied. He took it to the Supreme Court and won in an unanimous opinion and the miner, Henry Lewis got his 4,000 dollars.
For the people that are interested in Justice Black, I recommend a book titled Hugo Black: A Biography, by Roger K. Newman (Pantheon). It was a finalist for the Pulitzer Prize for Biography in 1995. It gives a fair and honest take of the Justice and his past in Alabama as a extremely successful attorney, whether in criminal, civil, local, state of federal trials.
Once again I am sorry about the inaccuracy.