Amidst supporters holding signs with messages including "Get Brexit Done", Johnson took the stage where he told the crowd that he had "no choice" but to hold an election, adding that Parliament was "paralysed" and "blocked", the BBC reported.
He said once Brexit was done, a Conservative government could get on with "better education" and "better infrastructure".
The Prime Minister told the audience the deadlock over Brexit had been like a "bendy bus jack-knifed on a yellow box junction (which) no-one can get round it and it is blocking in every direction", adding "we can't go on like this".
He said the thing he was "most proud of" during his 100 days in office was his Brexit deal.
Johnson also accused the Labour of "always running out of other people's money" and despite making a raft of his own spending promises, the Prime Minister said that the Party "know themselves that their policies for the economy are ruinous".
He added that a Labour victory would result in another referendum and a second vote on Scottish independence. "If I come back with a working majority, I will get Parliament working again."
Before launching the campaign in Birmingham, Johnson on Wednesday met the Queen at Buckingham Palace for about 20 minutes, marking the official start of the election period in the run-up to the December 12 polls, reports the BBC.
While the election has already been approved by MPs, the monarch still needed to sign a royal proclamation confirming the end of the last Parliament.
Parliament was dissolved - or formally shut down - just after midnight on Thursday, meaning all MPs revert to being members of the public, while government ministers keep their posts.
( With inputs from IANS )