Shaun Bailey said that after significant consideration, he has decided he can "no longer support the Prime Minster's leadership".
The West Bromwich West MP has previously urged his party to "get our heads down and start delivering now", but no longer feels this way after "much deliberation" and "soul searching".
He said that it is in the interests of the "country, the Conservative Party and my communities" that fresh leadership is needed.
Meanwhile the Express & Star understands that Dudley South MP Mike Wood has told the Chief Whip he believes it is time for Mr Johnson to go.
It comes as pressure has mounted on the Prime Minister over the latest sleaze scandal, which saw Walsall-born Chris Pincher suspended as a Tory MP amid claims he drunkenly groped two men.
Mr Bailey said on Wednesday: "In 2019, we secured an historic victory, particularly in the Black Country and for my communities it was as a result of that victory they were able to start pushing back against 50 years of Labour neglect.
"I am proud of the achievements that the Prime Minister has made, particularly getting Brexit done, our world beating vaccine roll out, investments in the public services and our response to Russia's invasion of Ukraine.
"It is also under this Prime Minister, that residents in Sandwell have finally had the intervention on Sandwell Council that they have been desperately calling for and this has given hope to so many people that the persistent issues at the heart of this local authority will be resolved.
"Over the last two years, we have seen record investment into our borough, whether that's £67.5million from the Towns Fund, £80,000 secured by myself to tackle flooding in Tipton, £50,000 to tackle congestion on the A461, £3million for Wednesbury Town Centre or the £22.5million I'm fighting to bring in for Tipton town centre.
"All of this has been made possible by this Government's commitment to levelling up.
"However, after much consideration, it is clear that it is in the interests of the country, of the Conservative Party and for my communities that we have fresh leadership.
"It saddens me to reach this conclusion and I have not done so lightly, but the information which has come to light, has left me to no other alternative than to believe that a new leader is the only way in which we can win the election and stop the travesty that would be a Labour Government.
"Regardless of what has been happening in Westminster, my faith and my focus will always be in the communities I represent and the area I am proud to call my home.
"Labour have spent half a century neglecting my communities, I will not allow them the chance to do it again."