"I think that Biden has been the candidate in the lead by default up to this point," he said.
"He has been essentially riding on the fumes of the Obama presidency. He doesn't have Obama's coattails anymore though to hold onto."
In addition, Sexton claimed that until the former Delaware senator ran on the Obama ticket in 2008, his name recognition was very low outside the Northeast and vicinity.
"People didn't know who he was," he said.
After eight years in the Obama White House, Biden became a household name. Yet another administration figure gained the mantle of Democratic presidential nominee in 2016.
Sexton said that onetime Secretary of State Hillary Clinton became the candidate who was to continue the Obama legacy.
"If he was so great, why wasn't he the guy then?" he asked about Biden.
In the wake of reports that Biden's campaign has considered cutting campaign appearances to minimize gaffes, Sexton said such a move might not be good for the candidate in the long run.
"If he wants to be the leader of the free world, we can't be coming up with ways to make this easier for him," the conservative radio host said.