She visited Walsall at the invitation of West Midlands Mayor Andy Street to meet former rough sleepers and the staff supporting them as part of the Housing First pilot scheme.
When she was Conservative leader he lobbied for the money to set up the programme.
Under the initiative around 400 people with a history of sleeping rough have been found accommodation to get them off the streets and their lives back on track.
In response to the furore over who covered the cost of decorating the current Prime Minster's 10 Downing Street flat, Mrs May said: "I think what people are going to look at when they come to vote next Thursday whether it is for a mayor or their local council is 'who's actually been doing the job for us' and if you look at councils we know that Labour and Liberal Democrat councils on average cost council taxpayers more than Conservative councils.
"Crucially what we have had in the West Midlands with Andy is that he doesn't just talk the talk, but he actually gets out there and delivers for people.
Watch Theresa May talking about the scheme:
"Every prime minister goes into that flat and they want to make it their own, they have different circumstances.
"There was just two of us; Boris has a young child, and a dog as well as his partner," she added.
She praised Mr Street's efforts in spearheading the Housing First project, attracting £250m in funding for the Dudley Metro Extension, £350m for the housing deal on brownfield sites plans to see 100,000 jobs created across the region.
She said she would be speaking to Walsall North MP Eddie Hughes, who is also the Rough Sleeping and Housing Minister, about promoting it further in the borough and elsewhere.
Mrs May, who served as prime minister from 2016 to 2019, said: "It has been hugely positive. It is really good to see something that's started off at government level as a project and actually talking to people who have been helped by it and whose lives have been turned around by Housing First. It's really good to see that sort of outcome.
"It's a combination of things. They've been helped, but crucially Andy has put homelessness and rough sleeping as one of his key priorities that the West Midlands was right up there, and getting the money from the Government and not just get the money, but do it."
"One of the key things is the important role that the council has and Walsall Council has been hugely supportive, without that the scheme wouldn't have been as successful as it had."
The programme is overseen by the West Midlands Combined Authority (WMCA) Homelessness Taskforce.
It is headed up by Birmingham City Council along with Dudley, Sandwell, Walsall, Wolverhampton, Coventry and Solihull councils in partnership with housing associations and homelessness charities.
West Midlands Mayor Andy Street said: "It's been a privilege for me to show Mrs May the outcomes from the initiative because three years ago we were lobbying her government to give us the funding and now we have got 400 people and the number of homeless people has fallen dramatically.
"We have the most reduced figures in the country."
Among those to benefit from Housing First in Walsall are former rough sleepers David Armishaw, of Pelsall, and Imran Reece Wall, 34, of Bloxwich.
Mr Armishaw, 28, said: It was really good to meet Theresa May.
"I'll confess that I'm a Labour fan, but I preferred her to Boris Johnson as prime minister.
"I thought she was down with the young people when she was the leader.
"She's a nice lady. She spoke to me about the support I have been getting from Housing First. I told her it was top notch."
He explained how he was sleeping on a bench on Church Hill when he took ill with hypothermia last November and was treated in hospital as a result.
Housing First has been funded to the tune of £9.6m over three years to provide a home and meaningful support.
In the West Midlands, a small budget is also given towards furnishings from the pilot funding and from money donated from the Change into Action homelessness service.