Prosecutors have argued Woodward lured Bernstein to a Lake Forest park and stabbed him 28 times because he was Jewish and gay.
Woodward's attorneys have already acknowledged his responsibility for the 19-year-old's death. But they have focused on the reasons behind the killing, saying they are "not black and white."
The defense says the killing was not motivated by Bernstein being gay. They say Woodward suffered from mental health issues and questions about his own sexuality.
Prosecutors have said Woodward killed Bernstein after the former high-school classmates reconnected in June 2017 and then agreed to hang out on Jan. 2, 2018. Bernstein was home from the University of Pennsylvania visiting his parents.
They accuse Woodward of intentionally luring Bernstein to a park in Lake Forest and of killing him within an hour of them meeting up. Bernstein's body was found eight days after he was reported missing.
They say Woodward had joined Atomwaffen, a neo-Nazi group, and targeted gay men on social media and dating apps.
"The defendant brought a folding knife, his Atomwaffen mask, a device to bury, a shovel and a sleeping bag and picked up Blaze Bernstein," a prosecutor said when the trial opened in April.
Thursday's testimony marked the trial's 26th day.
Because of previous court outbursts, Woodward was offered an option during his testimony: Sit at the witness stand with two officers behind him, or have his legs shackled and arms free with just one officer behind him.
He chose to have his legs shackled. He was taken to another room out of the jury's sight to be shackled.
His long hair covered his face as he sat on the stand and at one point his defense attorney asked him to push his hair back to show his face.
After acknowledging his responsibility for the killing, the defense has been focused on countering the hate-crime allegations, calling witnesses that include Woodward's family members.
"They're alleging it's a hate crime," former Los Angeles prosecutor Joshua Ritter, who is not involved in this case, told Eyewitness News.
"They're bringing in a lot more motive evidence you would not otherwise see in most murder cases. They're alleging this crime was committed because the victim was gay and Jewish."
The defendant's father, Blake Woodward, took the stand earlier in the day to discuss his son's upbringing and any signs he may have observed of violent behavior and racist or anti-gay statements. He said he couldn't recall his son making negative comments about gays or Jews.
But he did recall some angry outbursts or meltdowns in which he lashed out violently and would scream and destroy property. He also often wanted to be alone and not spend time with his family, his father said. By age 10, his father said, his son became obsessed with World War II, including weaponry and knives.
When Samuel Woodward took the stand, the questioning was focused on his relationship with his parents and older brother, Clay.
He also disclosed that he had been diagnosed with an autism spectrum disorder. When he learned of the diagnosis he experienced different emotions but ultimately didn't care, he said.
He said he had trouble talking to people at first because some saw him as strange.
He said he absolutely loves his family.
Woodward said he would often fight with Clay but he wasn't the aggressor.
Since his arrest Woodward said his brother has visited him in jail as recently as this year and their relationship has improved.
Thursday's testimony did not address the killing of Bernstein. His testimony is expected to continue Monday and the trial may wrap up by the end of the month.
If convicted of all charges, he faces the possibility of life in prison without parole.