His breathtaking performance in the velodrome was cheered on by thousands of fans, who watched him get silver in the men's individual 1km Time Trial.
The achievement marks an incredible turnaround, after he was forced into an emergency landing when his paragliding wing collapsed in 2009.
Colbourne, a former professional Welsh volleyball player, broke his back in the fall and underwent five months of gruelling physiotherapy just to learn to walk again.
His silver medal is all the more impressive as he only took up the sport three years ago.
He pipped compatriot and six-time Paralympic champion Darren Kenny, who was in third place before Colbourne's ride, to a medal position.
Speaking after today's event, he said: "It's very exciting. We have worked for the last 18 months towards this."
He thanked his coaches for getting him "into the best shape possible".
"Best wishes to Neil Smith for getting me back on a bike, albeit initially with stabilisers," added the 42-year-old.
It is hoped his silver will spark an expected gold rush this afternoon, and comes before fellow cyclist and medal hopeful Sarah Storey takes to the track.
Colbourne, a keen athlete from a young age, had previously represented Wales in volleyball and competed in three British Championships.
In May 2009, he plummeted 40ft to the ground and suffered life-changing injuries, but with a natural passion for sport, he went on to compete in the Welsh indoor adaptive rowing championships.
And in September 2009, he set himself a target of competing in his first para-cycling event and went on to win two gold medals at the Wales GB in Newport.
His remarkable commitment saw him being invited as a guest rider for the GB Para-Cycling Team before joining the squad in June 2011.
Earlier in the day, cyclist Sarah Storey beat her own world record on the track in the 3km C5 individual pursuit as the Duke and Duchess of Cambridge watched on.
The 35-year-old swimmer-turned-cyclist has won seven Paralympic titles since making her debut in Barcelona in the pool in 1992 and is aiming to add to her collection in London.
The record came after two medal hopefuls fell at the first hurdle.
Di Coates, who has spina bifida, failed to make the final in the women's R2 10m Air Rifle standing event.
Ben Quilter was also downbeat after being knocked out of gold medal contention in the under 60kg judo.The 30-year-old, who only has peripheral vision after being diagnosed with Stargardts Syndrome aged 10, was caught out and lost by ippon to Noura.He will contest the bronze medal later today.
The Games got off to a spectacular start last night in Stratford's Olympic Stadium with a stunning ceremony, including aerial acrobatics and guest appearances by the Queen and Professor Stephen Hawking.
Viewing figures released by Channel 4 showed the ceremony drew a peak audience of 11.2 million people - the broadcaster's biggest in a decade - and four times that of the opening in Beijing four years ago.
Craig Spence, the International Paralympic Committee's director of media and communications, hailed the "fantastic" ceremony a success.
He said: "It gave a reflection of all impairment groups and I think it showed how far the Paralympic movement has come. It had global appeal in Stephen Hawking. I thought his narration of the ceremony was fantastic. Every word he said meant something.
"I think there was a line in Sir Philip's speech that said the Paralympics will make you reassess how you think about yourself and how you think about others. I think Stephen Hawking's words did that as well."
Stuart Cosgrove, director of creative diversity at Channel 4, said it had received around "500 formally registered complaints and a bit of social noise on Twitter or Facebook" after breaking for adverts during the broadcast.
Mr Cosgrove told Radio 5 Live that should be measured against "the fact that we've invested significant sums of money to bring the biggest ever paralympics to television".
He said: "Those breaks were taken at strategic moments where we thought we could take legitimate advertising breaks to generate revenue that pays for the entire coverage."
UK Sport have set ParalympicsGB a minimum target of winning 103 medals from at least 12 different sports, with the overall goal of once again finishing second in the medal table.
Britain won 102 medals, including 42 golds, in Beijing four years ago to claim second place for a third consecutive Paralympic Games.
Last night, 62,000 people crammed into the stadium as millions around the world watched on. Prof Hawking delivered the powerful message to "Look up at the stars, and not down at your feet".
The highlight, however, was double amputee Afghan war veteran Joe Townsend, who flew into the stadium on a zip wire to begin the lighting of the cauldron.
Six Paralympians and former competitors - including Baroness Tanni Grey-Thompson - were bathed in gold as they "flew" into the stadium in a stunning acrobatic display.
Accompanying the athletics star were fellow Paralympians Robert Barrett, Kay Forshaw, Tony Griffin, Ian Rose and Marc Woods.
The ceremony heralded the start of 11 days of elite sporting action featuring athletes from across the world and before sell-out crowds who have made this the most successful Paralympic Games in history.
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