Now, the hammer thrower — who originally received bronze — has finally been awarded her silver medal from the Games at a special re-allocation ceremony at the headquarters of the German Olympic Committee (DOSB) in Frankfurt.
The 35-year-old has since retired from athletics, doing so after finishing fourth at Rio 2016 which was her final international competition.
Speaking at the ceremony, which was filmed by Olympic Channel for the documentary series 'Take the Podium', Heidler said:
"Holding the right medal in my hand today is a good feeling. It's a huge honour to receive it from the IOC president Thomas Bach."
Heidler's promotion to silver came after the original 'winner', Tatyana Lysenko of Russia, was disqualified for doping by the IOC in 2016 and stripped of her medal, after her control samples were re-analysed.
Lysenko was found to have the prohibited substance dehydrochlormethyltestosterone, also known as turinabol, in her specimen.
She was one of five athletes — three Russian and two from Belarus — who were disqualified from the 2012 women's hammer throw.
Poland's Anita Wlodarczyk, who initially won silver, was re-assigned the gold medal, which she successfully defended at Rio.
'Sad, angry and happy at the same time'
Four-time Olympian Heidler, who made her Olympic debut at Athens 2004, rued the missed celebrations for her second place at London 2012.
"When I found out that I will get a silver medal, I was sad, angry and happy at the same time. But mostly I was relieved that this competition ends in a fair way."
"I sincerely hope that a further improvement in the fight against doping will make late re-allocations unnecessary. As much as I am happy today, I can't get that moment of 2012 back," she added.
IOC President Thomas Bach, who was present at the medal re-allocation ceremony, said: "After the roller coaster of emotions in London, Betty Heidler has today finally received the deserved silver medal.
"I'm happy for her that she was able to experience this moment with her family and friends."
Since retiring from athletics, the 2007 world champion has continued her work for the German Federal Police.