Authorities said he put that bitterness into action in a stabbing and shooting rampage Friday night across the seaside California college town of Isla Vista that killed two young women and four men, at least half of them students at the University of California, Santa Barbara. Thirteen people were injured.
Rodger then apparently shot and killed himself inside the black BMW he used in the violence, authorities said Saturday.
The rampage played out largely as he laid it out in the public postings, including a YouTube video where he sits in the BMW in sunset light and appears to be acting out scripted lines and planned laughs.
''I'll take great pleasure in slaughtering all of you,'' Rodger, the son of a Hollywood director who worked on ''The Hunger Games,'' says in the video posted Friday and taken down by YouTube Saturday with a message saying it violated the site's terms of service.
''I don't know why you girls are so repulsed by me,'' he says in the video, describing his loneliness and frustration at never having had sex with or even kissed a girl. ''I am polite. I am the ultimate gentleman. And yet, you girls never give me a chance. I don't know why.''
Of the men he sees as rivals, he said: ''I deserve girls much more than all those slobs,'' and that after his rampage ''you will finally see that I am, in truth, the superior one, the true alpha male.''
The first three killed Friday were male stabbing victims in Rodger's own apartment whose names have not been released, Sheriff Bill Brown said Saturday.
Then, at about 9:30 p.m., the citywide shooting and vehicle-ramming rampage began.
His first stop was the Alpha Phi sorority, which he had called ''the hottest sorority of UCSB.''
''I know exactly where their house is and I've sat outside it in my car to stalk them many times,'' Rodger wrote in his extensive manifesto titled ''My Twisted World.''
No one answered the door after one to two minutes of aggressive pounding, but he soon shot three women who were standing nearby, killing two of them, 19-year-old Veronika Weiss and 22-year-old Katherine Cooper.
He then drove to a deli where he walked inside and shot and killed another UC Santa Barbara student, 20-year-old Christopher Michaels-Martinez, the sheriff said.
''Chris was a really great kid,'' Michaels-Martinez's father said at a news conference where he choked back tears and eventually collapsed to his knees in agony. ''Ask anyone who knew him. His death has left our family lost and broken.''
Michaels-Martinez was the last one killed, but rampage would continue as Rodger drove across Isla Vista, shooting at some and running down others with his car, twice exchanging gunfire with deputies. He was shot in the hip, but the gunshot to the head that killed him was thought to be self-inflicted, Brown said.
Thirteen people were injured, eight from gunshot wounds, four from the vehicle and one whose origin wasn't clear. Just four of the injuries were considered serious.
Deputies found three semi-automatic handguns with 400 unspent rounds in his black BMW. All were purchased legally.
Rodgers had been a student at various times in recent years at nearby Santa Barbara City College, but was no longer in any classes, the school said in a statement.
Authorities had had three contacts with Rodger in the past year, including one case in which he claimed to be beaten but deputies suspected he was the aggressor.
On April 30, officials went to his Isla Vista apartment to check on him at the request of his family. But deputies reported back that he was shy, polite and having a difficult social life but did not need to be taken in for mental health reasons, Brown said. Rodger says in his manifesto: ''If they had demanded to search my room... That would have ended everything. For a few horrible seconds I thought it was all over.''
Attorney Alan Shifman said the Rodger family had called police after being alarmed by YouTube videos ''regarding suicide and the killing of people'' that Elliot Rodger had been posting.
Brown called the tragedy ''the work of a madman'' and said the videotape posted by Rodger the night of the killings is a ''particularly chilling one, in which he looks at the camera and talks about what he is about to do.''
Earlier Saturday, Shifman issued a statement saying 'Hunger games' asst director Peter Rodger believed his son was the shooter. The family is staunchly against guns, he added.
''The Rodger family offers their deepest compassion and sympathy to the families involved in this terrible tragedy. We are experiencing the most inconceivable pain, and our hearts go out to everybody involved,'' Shifman said.
Isla Vista, a half-square-mile town centered on university life with outdoor cafes, bike shops, burger joints, sororities and fraternities, was shrouded in fog and unusually quiet Saturday.
Police tape crisscrossed Isla Vista streets, while blood was still visible on the asphalt. Bullet holes pierced windows of a parked car and the IV Deli Mart. A small shrine of flowers was growing outside the business, whose floors inside were stained with blood. For much of the day, the wrecked BMW driven by the shooter remained on the street, its windshield smashed in and its driver's door wide open.
UC Santa Barbara senior Kyley Scarlet said she heard the BMW smash to a halt outside a house she was in. Scarlet, who is a former sorority president, said two women from a sorority next door were killed on the lawn, where a pile of flowers grew on Saturday.
Crying students wandered up to the spot, shook their heads and hugged each other.
Scarlet said she was very disturbed by the video describing his anger at sorority girls.
''It's hard thinking my actions, being part of a sorority, led him to do this,'' she said.