"It's a dream come true for me and I want to be a role model -- not only for disabled people in my country but also for the able-bodied who lose courage," said Baig, whose right leg was left shorter than his left by polio in childhood.
The 33-year-old post office clerk who thought life was over when he couldn't run as fast as the other boys growing up, is one of four athletes representing Pakistan at the London Paralympics from August 29 to September 9.
He will compete in the 200 and 400m, hoping to replicate the success of Pakistan's first paralympian, long jumper Haidar Ali, who won silver in Beijing in 2008.
"I always wanted to run like the other boys but my disability hindered that. I made a promise to myself that one day I will run and win, and that day will come during the London Paralympics," he said.
Ali heads the Pakistani contingent. Aneela Beg will compete in women's 100m and shot-put, and Mohammad Naeem in the 800 and 1,500m.
Baig won silver in the 400m at the Asian Games in Dohar in 2006, but London will be his first Olympics as a competitor.
He represented Pakistan in Beijing as an official after not being selected to compete -- a disappointment he doesn't want to discuss.
Born and brought up in the industrial town of Faisalabad in Pakistan's political heartland of Punjab province, Baig struggled for years after contracting polio.
"I used to feel dejected whenever I watched boys my age play, run and do the usual things of life without facing any problems."
He declined to be drawn on the Taliban's recent ban on polio vaccinations in parts of Pakistan's northwestern tribal belt, jeopardising the health of 240,000 children.
But bizarrely, he says what changed his life was watching an obscure film as a teenager about a man who overcame adversity to help his nation win a war.
"It taught me a lesson that I should fight and pave a way to becoming a role model for my country's youth," said Baig.
He finished school and went to university, completing a Bachelor's degree that enabled him to get a job as a clerk in the Faisalabad post office.
But the track was always his first love.
"I trained and trained hard because I knew that if I want to achieve the goal of representing Pakistan and become a role model I have to work hard," said Baig, who started at club and regional level.
His first international chance came in the 2006 Asian Games.
"That silver medal made me realise that nothing is impossible in life," said Baig. "Haider's success in the last Paralympics was a further motivation and now I want to win my own medal," said Baig.
In cricket-mad Pakistan, Baig feels put out that other sports don't get the same attention despite a series of spot-fixing scandals that have brought shame on some of Pakistan's most gifted cricketers.
"It is disappointing that cricket gets all the media attention in our country," he said. "Cricket brought a bad name for our country so we must win in other sports to bring about a change."
Other than winning a medal, Baig would love an autograph from Jamaica's sprint king Usain Bolt, who made history by retaining his Olympic titles in the 100 and 200m.
"Bolt is an inspiration for the athletes of the world," said Baig. "I hope I get a chance to meet him in London."