Michael Fabricant is backing Foreign Secretary Ms Truss for Tory leader, saying she has the "character, loyalty and ability" needed to run the country.
The Lichfield MP criticised former Chancellor Rishi Sunak for sticking rigidly to the Treasury line and failing to address the cost of living crisis.
He said Mr Sunak's role in ousting Boris Johnson was another mark against his candidacy, and questioned whether he was committed to supporting the West Midlands.
Mr Fabricant said: "I fear that when Rishi was Chancellor, he was ‘captured’ by the civil servants into conventional Treasury thinking unable to find a way out of the world-wide cost of living crisis.
"Whereas the United States and other countries have decided to borrow in order to fund support for their citizens, Rishi Sunak sticks to the Treasury line calling for greater restraint and higher taxes when times are already tough.
"Liz Truss recognises this. I also believe that while Rishi’s targeted and generous support for those most needy, provided when he was Chancellor, was welcome, it fuelled inflation.
"But most of all, I believe that while Liz Truss will help the West Midlands, Rishi has concentrated all his focus on the north of England and has not always engaged constructively with the West Midlands Metro Mayor.
"While that is understandable as he represents a Yorkshire seat, this does not help our region."
Mr Fabricant added that voters in the West Midlands would respect Ms Truss's loyalty to Mr Johnson. "To me character and loyalty count as much as ability and Liz has all three," he said.
"She will make an effective Prime Minister, continue to provide support for Ukraine, and make the most of Brexit. She has my vote."
Meanwhile West Midlands Mayor Andy Street has called for a series of "concrete commitments" from the next PM.
He has demanded support for the automotive sector and said it was vital the Government's promise to level up the country was carried through. He also said the next PM must "get a grip on the cost of living crisis" and restore people's faith in politics.
"The candidate who can do this will have my vote," Mr Street said.
Ms Truss is the short-priced favourite to win the leadership race, which will be decided on a members' vote.