Mr Johnson was visiting West Midlands Metro's Wednesbury depot, where he chatted to workers along with West Midlands Mayor Andy Street.
Mr Johnson has backed Andy Street's plans for extending tram lines and services and increasing the number of stations.
He said it was crucial that connectivity around the region was improved to enable people to travel for work using "good, affordable transport".
The Prime Minister said: "As a former Mayor I totally understand what he is trying to do and it is bang on the money.
"You have got to connect your centres of economic opportunity better. You've got to help people to get to the high quality, highly skilled jobs.
"So putting in 150 more miles of tram line is a smart thing to do, as is 50 more stations."
During his visit, Mr Johnson sat at the controls of one of the trams and was given an overview of how to operate it.
His visit comes ahead of the West Midlands' mayoral election next month.
Pledge to protect our clubs from super league threat
The Prime Minister has pledged to protect the region’s great football clubs by blocking a plan for a controversial breakaway European Super League.
Boris Johnson said he will work with the game’s administrators “to make sure that this doesn’t go ahead in the way that it’s currently being proposed”.
Manchester United, Liverpool, Arsenal, Chelsea, Tottenham and Manchester City have announced they have signed up to the plan, joining teams from Italy and Spain.
Mr Johnson said the scheme was not the way forward for football in the UK, as it would see a small number of clubs “sucking an awful lot of cash” out of the game – to the detriment of outfits such as Villa, Wolves and Albion.
During his visit to the West Midlands, Mr Johnson said: “The issue that is being raised is that first of all, if this thing were to happen, then people would have to go and pay a lot of money travelling overseas to follow their local club whose name is not just a global brand, but it’s the name of an historic English place with a huge amount of history attached to it.
“The second thing is that the proposal does seem to involve sucking an awful lot of cash into a particular group of clubs and making life perhaps tougher for the other clubs and taking out the possibility of there being giant killer moments that make football so exciting and give such hope and encouragement to fans up and down the country.
“It doesn’t seem to me to be a very good idea from the point of view of football or fans.
“We are going to work with the FA, with the Premier League and with UEFA to see where we go. We don’t think this is the way forward.
“We are going to look at everything that we can do to make sure that this doesn’t go ahead in the way that it’s currently being proposed.”
West Midlands Mayor Andy Street has also spoken out against the plans. He said: “Proposals for a European Super League are absolutely appalling and we must stand together to stop them.
“Creating a closed competition that serves only the wealthiest clubs goes against the very essence of fair play in sport, and shuts the door on all other clubs aspiring to be part of the game’s elite.”
Mr Street said he has reached out to clubs at all levels across the West Midlands and vowed to work with Ministers to fight the plans.
“Having met with our regional clubs several times during the pandemic, I stand ready to support them again over these disgraceful super league proposals,” he added.
‘Cruel and intolerable’ crime of stalking to be targeted
Boris Johnson says he is committed to stamping out all forms of harassment as it emerged there has been a huge rise in stalking cases over the past year.
The Prime Minister described stalking as “cruel and intolerable” and vowed that new measures giving police greater powers to stop perpetrators from making contact with their victims would “make a difference”.
He was speaking to mark National Stalking Awareness Week, where agencies across the country join together to raise awareness of stalking and its impact on victims.
It comes after the Suzy Lamplugh Trust charity said it had received nearly 20,000 calls in the past 12 months, with stalking victims left feeling like “sitting ducks” in many cases due to lockdown.
Stalking protection orders were introduced in January 2020 in a bid to make it easier for victims to get support.
Mr Johnson said his Government would continue to work with police and charities to tackle stalking.
Speaking during his visit to the region, he said: “Stalking is cruel, it is psychologically debilitating, it’s absolutely intolerable. We have got to give women – and it’s largely women obviously – protection.
“That’s why we are bringing in the measures that we are to give police greater powers to stop people from making contact with the victims.
“From a very early stage, if they can be prevented from hassling the individual we hope that will make a difference.
“We’re tying this together with what we’re doing with our Domestic Abuse Bill, where again people can feel very threatened and oppressed for a long time, and they need the security of knowing that someone is on their side.
“This kind of stuff can ruin people’s lives, so we’re very, very keen to stamp it out.”
Stalking cases have more than doubled in some parts of the country, including the West Midlands, since the start of the pandemic, with the issue said to have become more widespread due to some perpetrators targeting their victims online while being stuck at home after being furloughed.
And campaigners say some stalkers have also used lockdown to their advantage to physically harass their victims at a time when they are more vulnerable because of the stay at home rule.
It is feared some have been able to hide in plain sight because the use of face coverings has allowed them to follow their victims without being spotted.
Suky Bhaker, chief executive of the Suzy Lamplugh Trust, said many victims have felt “trapped in their homes without the normal avenues of support”.