Saturday Night Live/screenshot
During the show's cold-open sketch, Ferrell went down the list of Republican front-runners in order to question their qualifications for the Oval Office.
But because he was impersonating Bush, Ferrell botched most of the criticism.
Ferrell cracked up over "knucklehead" Donald Trump's appearance and then attacked the real-estate mogul's plan to temporarily stop Muslims from entering the US.
"He says he wants to keep all the Muslims out. Yeah, that's a great idea," Ferrell said sarcastically. "That's impossible to implement and not what this country is about. Heck, that's like saying, 'Let's keep all the leprechauns out.'"
Ferrell also hit retired neurosurgeon Ben Carson's soft-spoken nature.
"Dr. Ben Carson, I can barely hear him when he talks. I'll tell you something: That's not going to work when you have to go to China or Azerbaijan, where you have to TALK LOUDLY SO THEY WILL UNDERSTAND," Ferrell said, mispronouncing "Azerbaijan."
Of former Hewlett-Packard CEO Carly Fiorina, Ferrell quipped, "She's not qualified in any way to be president. In many ways, she reminds me of me. But she isn't me. I am me."
Ferrell's final target was Bush's brother, former Florida Gov. Jeb Bush (R), whom he compared to broccoli.
"Jeb, oh boy. Poor Jeb. You've got to admit it's a pretty good plot twist that I turned out to be the smart one," the actor reflected, turning to the exclamation mark on Jeb Bush's campaign signs.
"Of course, I wish you would have asked me about the exclamation point on the end of his name," he continued. "Look, I don't like the taste of broccoli but it doesn't get any tastier if you call it BROCCOLI!"