Frazier Glenn Cross, 74, a former senior member of the Ku Klux Klan who is representing himself at trial, could be sentenced to death if convicted in the April 2014 shootings in Overland Park, Kansas, a suburb of Kansas City.
He also is charged with the attempted murder of three others. Cross has pleaded not guilty to all the charges.
Cross admitted to jurors on Friday that he killed a man, woman and teenage boy and tried to kill more people during a shooting spree on the eve of the Jewish Passover holiday. None of the victims were Jewish but Cross he did not know that at the time.
He said he believes Jews have committed genocide against white people, and control both the media and Wall Street to the detriment of white Americans.
"I had no criminal intent, I had a patriotic intent to stop genocide against my people," said Cross, who is also known as Glenn Miller.
Seated on the witness stand, Cross described himself as a husband and father who owned a farm in southwest Missouri. He said in the days before committing the murders he researched what he sees as the demise of the white race and decided he had to take action
"I hate Jews," Cross said. "They are the ones who destroy us."
If convicted, the second phase of the trial next week will determine if he should be executed.
Johnson County District Judge Thomas Kelly Ryan denied an effort by Cross to show videos that reflect his political and religious views, but said he may do so if there is a penalty phase.
Cross is charged with killing high school student Reat Underwood, 14, and Underwood's grandfather, 69-year-old William Corporon, outside the Jewish Community Center of Greater Kansas City, as well as Terri LaManno, 53, outside a nearby Jewish retirement home.
Prosecutors in Kansas rested their case on Thursday after playing a recorded call from his jail cell in which Cross expressed surprise that his victims were not Jewish.
Prosecutors also presented witnesses, video and forensic evidence earlier this week that they have said connects Cross to the killings.