The presumptive Republican nominee told CNN's Jake Tapper on "State of the Union" Sunday that he could deliver his response as soon as Monday.
"I think I'm going to devote a retort to her speech. Maybe I'll do it on Monday, before the election" in California and four other states, Trump said.
He mocked Clinton for working with speechwriters on the San Diego remarks. And he swatted away Clinton's criticisms -- she cast him as "temperamentally unfit" for the presidency and driven by personal feuds -- by insisting he has "very strong, very thick skin."
"Most of the things, many of the things she said, are wrong," Trump said.
Trump also defended his claims that he opposed the Iraq War before it began.
"I was against it from before it started," he said.
It's clear Trump opposed the war by 2004, but there's not yet any public evidence that he opposed it before the war began in 2003.
Asked on Howard Stern's show in 2002 whether he supported then-President George W. Bush's push to go to war, Trump said, "Yeah, I guess so."
He cast his comments in that 2002 interview as wishy-washy, saying they show he was moving toward opposing the war.
"That interview was substantially before the war started," Trump said. "First time I was ever asked the question."
In a separate interview on "State of the Union," Clinton bashed Trump over his Iraq War claim.
"Well, he supported it," the Democratic front-runner said. "We have evidence and audio of him supporting it, so I think that's another example of him trying to rewrite history."
Trump on protests
Trump also criticized protesters who have been involved in violent clashes outside his campaign events, calling them "thugs" planted by Democrats.
"They're thugs," he told Tapper. "The people that are outside -- they're thugs and they're agitators. They're bad people. I think they're sent by the Democrats."
Asked for evidence to back his claim that the protesters are being sent by Democrats, Trump said: "Well, they have Bernie signs."
Anti-Trump protesters clashed with his supporters outside a rally last week in San Jose. Previously, protesters had thrown rocks and bottles and burned signs in Albuquerque, New Mexico, and protesters and Trump supporters fought in Chicago at an event Trump ultimately canceled.
Trump said police should be "very strong" with protesters at his events -- but said he's not criticizing police for how they've handled the protests so far.
"I think the police forces are being treated very unfairly in this country. They're afraid to do anything because they don't want to lose their jobs, they don't want to lose their pension, they don't want to be criticized," he said.
Trump on judge attacks
Trump also vociferously defended his claims that a judge overseeing a lawsuit against Trump University is biased because of his Mexican heritage -- pushing back against criticism that his objections are racist.
The presumptive GOP nominee told Tapper that U.S. District Court Judge Gonzalo Curiel, a federal district judge in the Southern District of California, has made "rulings that people can't even believe."
"He's proud of his his heritage. I respect him for that," Trump said, dismissing charges that his allegation was racist. "He's a Mexican. We're building a wall between here and Mexico."
Trump first broached these waters in an interview with The Wall Street Journal
published Thursday, in which he said Curiel, who was born in Indiana
, had an "inherent conflict of interest" in the Trump University lawsuit.
"If he was giving me a fair ruling, I wouldn't say that," Trump told Tapper, pointing again to Curiel's background. "I think that's why he's doing it."
"I'm building a wall. I'm trying to keep business out of Mexico. Mexico's fine," Trump continued. "He's of Mexican heritage, and he's very proud of it, as I am of where I come from."