Your challenge, if you choose to accept it, is to create a timeline in which Reverend Dr. Martin Luther King, Jr. becomes President of the United States.
It depends much about POD but if civil right activism starts soon after WW2 and it gains more support from federal government. Anyway, what earlier POD that easier.
I think it would have been possible if he were not assassinated and it took place in the 1970's when candidate such as Carter and Ford were weak. Watergate would still have to taken place and Vietnam had the same outcome. Martin Luther King had wide respect among both parties. He was good friends with Billy Graham, who if he endorsed him, could help deliver states in the south.
King voted for Kennedy.J. Edgar Hoover died in 1972, so he won't be too much of a problem. If King doesn't get killed, I could see him making a possible run in 1976 or 1980 in either party. As far as I know, he was a registered Republican in the 1950s, so I could see him running as a Republican in 1976 or 1980 against Ford (He might pull a Reagan Primary Challenge) or take on Carter in 1980.
But, I could easily see King try to pull an Eisenhower and have him try to be courted by both parties.
Exposure of his infidelities and his disbelief in God would remove the doctor and reverend from his name, if that has any effect.