Lewandowski was to make his debut on Erin Burnett's "Outfront" program on Thursday night, a spokeswoman said.
The combative Lewandowski now joins a press corps that he was occasionally at odds with during the Trump campaign. That includes a CNN producer: Noah Gray tweeted last November that Lewandowski had threatened to pull his credentials when he tried to film a demonstration at a Trump rally.
Lewandowski also was charged with misdemeanor battery last spring following an altercation with a female reporter from Breitbart News who had tried to ask Trump a question following a rally. The charges were later dropped.
CNN has used a handful of Trump surrogates as commentators during its political coverage, most prominently Jeffrey Lord and Kaleigh McEnany.
Lewandowski may be limited in what he can say on the air. The Associated Press has reported that Trump requires nearly everyone working in his businesses and presidential campaign to sign nondisclosure agreements preventing them from releasing confidential or disparaging information about him.
After his firing on Monday, he gave interviews to a number of reporters and remained positive toward Trump, saying he did not understand why he was fired. The campaign let him go following a rough three weeks for the presumptive Republican nominee.
"CBS This Morning" co-host Norah O'Donnell asked Trump during an interview on Tuesday how influential his children were in the decision to fire Lewandowski.
"Well, my children are very smart and they're not much involved in the campaign. ... But I do rely on them from the standpoint of I like to listen to intelligent people, and they're very intelligent," Trump said. "Corey's done a great job. You know, I am a big fan of Corey. I like him a lot. He likes me a lot. ... But, you know, we are going into a different phase and I have a very good team of people. And I think we're gonna do very well, and I think the early polls are showing that we're gonna do very well."
"But was part of that your children saying, 'Look, we need to gear up. This is a national election. We've got a lot of battleground states. We need to be raising more money,'" O'Donnell asked.
"No, it really wasn't. I'd tell you if it was. It's no big deal." Trump said. "I mean, there's nothing wrong if they did say that. I mean, I read where my children didn't like Corey. They like him very much. I mean they ... felt bad. Two of 'em really felt badly about it, because they didn't want that. They like Corey."
The campaign manager's former boss tweeted two disparaging messages about CNN on Thursday, posting Breitbart News articles critical of the network.
"The Clinton News Network is losing all credibility," Trump tweeted. "I'm not watching it much anymore."
Lewandowski's hiring by CNN was first reported by Politico.