The West Midlands Mayor is backing Ms Truss in the Tory leadership race, saying she has the policies needed to make "levelling up a reality" for the region.
Foreign Secretary Ms Truss was in Perry Barr over the weekend to take in the Commonwealth Games at Alexander Stadium alongside Mr Street.
She set out her vision to level up the country "in a Conservative way" by ensuring that years of "underinvestment" in areas such as the West Midlands is "fixed".
Among the measures she unveiled included plans to open 'investment zones' on brownfield sites to kick start the creation of new model towns such as Bournville in Birmingham.
Ms Truss says she would aim to protect the green belt by scrapping Whitehall housing targets and working with local communities to identify sites ripe for redevelopment to "turbocharge" commercial and residential schemes.
She has also pledged to review business rates and levelling up funding – to make sure government cash gets to the areas that need it most – and to continue the current policy of opening new rail lines and stations to improve transport links.
Ms Truss said: "My mission as Prime Minister will be to level up opportunity and realise aspiration no matter who you are or where you live. I know that levelling up our country is now more important than ever, and the best way to achieve this is by going for growth.
"You cannot tax your way to growth. That’s why my bold plan will kickstart the economy and level up in a Conservative way, standing up for people who do the right thing, who work hard, and want a better life for themselves and their children - no matter where they are from."
Mr Street announced his backing for Ms Truss after she had pledged to support a range of measures including a West Midlands gigafactory, the Midlands Rail Hub and the trailblazer devolution deal.
He said: "Liz Truss understands that our regions represent a potential gold mine of growth, the West Midlands especially. When we fire on all cylinders, the whole of the UK stands to benefit.
"She has a bold vision for our regional economies, with the policies we need to make levelling up a reality.
"Her plan for investment zones, for instance, will give us a powerful tool for unlocking new investment, jobs, and growth."