Cuban said, "If he had any leadership skills whatsoever ... he would be saying to people: 'I will get this fixed.'"
The whole country is listening to what Trump has to say, Cuban said during an interview on CNBC's "Halftime Report."
Fellow "Shark Tank" star, Kevin O'Leary, disagreed with Cuban.
"You don't like his style. That's what I think," O'Leary told Cuban. "Trump has a style — he makes statements — but at the end of the day, my assumption is that for the good of all North America, including Mexico, he is going to be pragmatic."
To which Cuban responded, "Thank you, Peter Thiel."
But Trump won't accept fault or take responsibility, Cuban argued. The Dallas Mavericks owner said that the president has instead chosen to rant and rave about "leaks" to the media.
Cuban's comments to CNBC echoed those he made earlier Friday on Twitter.
Disclosure: CNBC owns the exclusive off-network cable rights to "Shark Tank," which features Mark Cuban and Kevin O'Leary as judges.