He decided that intelligence is determined by our genes, which most people agree is partially true. Then he decided that black people had less of these good genes, and it all went to hell. Highlights of his self-destructing career path include a Senate campaign on the platform of sterilizing people with sub-100 IQs, and becoming the only Nobel Prize winner to answer a call for donations to a superbaby sperm bank.
According to IMDB, he also played a rapist in Showgirls. Movie makeup is amazing these days!
Robert Graham, the founder of the sperm bank, sent out invitations to 25 or so Nobel Prize winners as part of a mission to encourage reproduction of the best and brightest before the world was flooded with morons. Three actually participated but none admitted it except for Shockley, who also added that the Nobel winners that refused to donate should be ashamed. Graham advertised his... product... as a selection of "the choicest genes... above average is not enough." For some reason, the public responded negatively to this, forcing Shockley to, uh, pull out, so to speak. Someone out there was buying though, because the bank stayed in business for 19 years.
And who could blame him for wanting to spread his sexy superhero genes?
As he saw it, all the hubbub was because everyone was misunderstanding his views, blowing it out of proportion when he said innocent things like, "If you found a breed of dog that was unreliable and temperamental, why shouldn't you regard it in a less favorable light?" Communication issues aside, he literally did want to reduce the black population and sterilize low-IQ people, and all his care in selecting interviewers and tape-recording every conversation did nothing to clear up the "misunderstandings" he thought were causing his problems.
How did this affect his career? Well, Stanford really didn't do anything about it except let him keep on keeping on, even making him a professor emeritus when he retired (about 10 years after he started airing his views on eugenics). That's Latin for a retired professor who is so awesome that he will be given an honorary title for the rest of his life and will always have a home at Stanford.
Yes, it's really called Leland Stanford Junior University. One of the more useful facts I learned at Berkeley.