King was spreading the message, "Let's have a nation in unity... Let's talk about the character of the nation," Armey told CBS News chief Washington correspondent Bob Schieffer on CBSNews.com's Washington Unplugged. "This is exactly what Glenn Beck's doing."
Armey said King would disapprove of the notion that people with differing opinions should have to go to a different spot to express themselves.
Schieffer pointed out that some people are upset because of Beck's past, racially divisive comments, such as saying that President Obama "has a deep-seated hatred for white people or the white culture."
"I've never heard him say these things," Armey said.
Nevertheless, he said, the message of Saturday's "Restoring Honor" rally is "not about a single person or a quarrel between two people."
Armey's organization FreedomWorks has helped mobilize Tea Party activists from around the country, a number of whom are expected to gather on the National Mall for Saturday's event.
Armey said his organization has a complementary relationship with Beck. While the television host serves as the "instructional arm of the grassroots movment," Armey said, "We are the activist arm."
The rally on Saturday, he said, will give people the opportunity to "immerse yourself in the heritage of the nation."
The Tea Party, Armey said, will be a "big problem for establishment Republicans" in this election cycle. Republican insurgent candidate Joe Miller, who appears to be, is just the latest example, Armey said.
However, the Tea Party will prove to be a bigger problem for Democrats, he added.
While Democrats are trying to portray Tea Party-backed candidates like Miller as, Armey said that line of attack doesn't hold water. Positions like being in favor of privatizing Social Security are not extreme, he said.
"What you're seeing with Democrats today... are the acts of, frankly, a panicked political party," he said. "They don't know how to stem the tide."
Watch Friday's Washington Unplugged above also featuring CBS News' Kaylee Hartung on the opening of the Newseum's "Covering Katrina" exhibit, marking the 5th anniversary of Hurricane Katrina.