A student at Shoreham College, the 14-year-old joined the Portslade and Shoreham Division in 2017.
He was named District Cadet of the Year in December and is only the second-ever cadet from the division to win the title.
Yesterday, Oliver won the regional title in the annual competition and will now represent St John Ambulance at ceremonial occasions throughout 2019, including the St John’s Day event at St Paul’s Cathedral in June and the annual Young Achievers reception, where he will meet Princess Anne, the charity’s commandant in chief, youth.
Oliver said: “It’s absolutely amazing and I am proud to have won. The weekend has been great and I am looking forward to an exciting year alongside my fellow cadets.”
He was one of 32 young people vying for the title during the national event, at Eastwood Hall in Nottinghamshire, over the weekend of February 15 to 17.
Oliver regularly volunteers as a cadet first aider at events, including the Brighton Marathon and at the Amex Stadium, where he was part of a team that helped treat a man who had a heart attack.
His experience with St John Ambulance has sparked an interest in medicine, which he hopes to develop into a career.
Oliver said: “Becoming a St John Ambulance cadet has been life-changing. I was looking for a volunteering opportunity to help with my Duke of Edinburgh Award, so joined the local unit.
“I found I wanted to help people and enjoyed this aspect of volunteering with St John. I’m now hoping to study medicine at UCL and go on to become a trauma doctor, or work in the Royal Navy as a medic.
“I can’t believe I’ve won the Regional Cadet of the Year title but it shows just how far I’ve come and what can be achieved in a short space of time as a young first aider.”
For the competition, challenges included delivering a presentation on St John Ambulance’s future, an interview with chief executive Martin Houghton-Brown, group discussions and designing a uniform for space-age volunteers.
Ann Cable, chief volunteer, said: “Our Cadet of the Year competition is always one of the highlights in our calendar and this weekend has been truly inspirational – huge congratulations to Ollie.
“Ollie is an accomplished cadet who is keen to represent the charity and our young volunteers in a positive light, particularly with external organisations, so that people know all about what St John Ambulance can offer.
“All of the cadets have been fabulous. I’m lucky to work with so many talented young people who have each told their own story about how they have travelled through St John, many overcoming personal challenges along the way.
“Their energy, enthusiasm and passion for making a real difference in their communities is awe-inspiring and I wish Ollie and his fellow winners great success in the future.”
Oliver is Deputy Member of Youth Parliament for East Arun, Adur and Worthing, and has also been selected to be a Lord Lieutenant Cadet for West Sussex during 2019.