Corey Lewandowski, the former campaign manager for Donald J. Trump, is joining CNN as a political commentator, effective immediately, a spokeswoman for the network said Thursday.

Mr. Lewandowski was fired by the Trump campaign on Monday after increasing concerns from allies and donors, as well as Mr. Trump’s children, over whether he could handle a national campaign against Hillary Clinton’s well-financed operation.

Mr. Lewandowski’s contract will make him exclusive to CNN, meaning he won’t be able to appear on other networks. CNN currently has another Trump surrogate, Jeffrey Lord, as a frequent guest.

The Lewandowski hiring was first reported by Politico.

Cable news networks have long turned to former campaign operatives to provide commentary. But Mr. Lewandowski’s hiring is fraught: He was charged with battery for grabbing a reporter at a Trump campaign event in March; he is known for sometimes combative interactions with the news media; and his rise and fall at the Trump campaign made him a singularly polarizing figure.