willing to sacrifice his own career to uplift a cause for the greater good
I recommend reading Caro's biography series on LBJ. I think you would find this statement to be not accurate. He was willing to alienate (white) Southern voters because his one overarching goal in life was to be (and to stay) President and (white) Southern voters were never numerous enough to ensure that. To his credit, LBJ seemed to be very much not racist personally, but fixing racism was never a goal of his.