MSNBC's 7 p.m. slot has been occupied by a series of rotating hosts for the past three months.
Reid has been seen as the front-runner for the job since Matthews departed as her star power continues to rise on the progressive network, with a social media following that has risen to 1.7 million followers.
The Harvard University grad is also part of MSNBC's special coverage of political events, including election nights, while also serving as a fill-in host for Chris Hayes and Rachel MaddowRachel Anne MaddowPaul, Cruz fire back after Fauci says criticism of him is 'dangerous' An unquestioning press promotes Rep. Adam Schiff's book based on Russia fiction Biden's safe-space CNN town hall attracts small audience, as poll numbers plummet MORE in prime time.
She would serve as MSNBC's first prime-time African American host.
Reid currently hosts "AM Joy" which runs weekend on the network, but she also frequently pops up as a guest host or for appearances on MSNBC throughout the week.
She hosted the "Reid Report" on MSNBC before launching "AM Joy" in 2016.
Reid is also scheduled to host a special on Friday night in the 7 p.m. slot. The special will feature members of the Congressional Black Caucus, who have been instrumental in a police reform bill that the House is scheduled to be voting on later on Wednesday.
Matthews, 74, resigned several months ago over sexual harassment accusations, which he conceded were "highly justified."
The Hill has reached out to MSNBC for comment.
Reid was at the center of controversy two years ago and apologized for homophobic remarks she made on her now-defunct blog.
The MSNBC host initially denied writing the posts, blaming them on hackers, before publicly apologizing.
Reid said in a lengthy statement that "there are things I deeply regret and am embarrassed by, things I would have said differently and issues where my position has changed."
"While I published my blog, starting in 2005, I wrote thousands of posts in real time on the issues of the day," Reid said. "There are things I deeply regret and am embarrassed by, things I would have said differently and issues where my position has changed. Today I’m sincerely apologizing again."
"I’m sorry for the collateral damage and pain this is causing individuals and communities caught in the crossfire," she continued.