Even at the age of 11, racing hurdles for the first time, she made an immediate impression on coaches at the Don Valley stadium in her home town of Sheffield, West Yorkshire – particularly Tony Minichiello who took her under his wing and guided her to Olympic glory in London 15 years later.
After that first taste of athletics Ennis took up the sport in earnest, and became National Track and Field high jump champion at 14 with a leap of 1.70m, a title she would defend two years later.
But she really came to prominence after switching to heptathlon, and in 2005 took gold at the World Junior Championships, third place in the World University Championships and first atthe All England Athletics Championships.
Training for several hours a day, six days a week elevated Ennis to the point where she was seen as a medal hope for Team GB at Beijing in 2008 – until disaster struck in the form of a serious bone fracture, meaning she would miss the Games.
But Ennis proved resilient as well as gifted, and with the help of Minichiello recovered to win the World Championships the following year — even changing her long jump style to lead with her weaker foot – followed by the World Indoor Championships title in 2010.
By 2012 she had become perhaps Britain’s most famous contemporary athlete – a fact not lost on visitors in London for the Games, where her face gazed out from posters all over the capital. Travellers arriving at Heathrow Airport were met by her image almost as soon as they stepped off their planes.
But despite being an elite athlete Ennis admitted to often being physically sick with nerves before competitions and felt deeply the pressure to win at her home Games from an expectant nation.
Ennis, 26, put in 10,000 hours of training for the Games. A typical day would include plyometrics drills – short, explosive bursts of exercise – in a park in Sheffield, weights sessions and endurance sessions to prepare for the 800m.
And it was that event, the final contest of the 2012 Heptathlon that sealed Ennis’ place in the hearts of spectators in the Olympic stadium and watching around the world on television.
After a strong start in the first event, the 100m hurdles, Ennis broke the British hurdles record and smashed her own personal best with an exhilarating run of 12.54secs, before performing solidly in both the high jump and the javelin, her weakest event. Ennis went into the 800m with a commanding 188-point lead. And it was here that she became a true Olympian.
Knowing she could comfortably take gold overall in the competition without winning the race, she produced a world-class , bursting from the middle of the pack to finish first with a British and Commonwealth record score of 6,955 points and provoking ecstatic scenes in the stadium.
The pressure was off, and the face of the Games had delivered. Afterwards she said: ‘I can't believe I’ve had the opportunity to come to my first Games in London and won an Olympic gold medal. It’s unbelievable.’