Sir Mo Farah insists it is the right time to quit the track despite missing out on a fairytale finale.
The 34-year-old signed off at the World Championships in London on Saturday with a silver medal in the 5,000 metres, and his next challenge will be road races including marathons.
Ethiopia's Muktar Edris denied Farah the dream double after the Great Britain star had already won the 10,000m title last week.
Farah, who has won 10 global titles including an Olympic double at London 2012, will retire from the track following the Diamond League final in Zurich on August 24 and is content with his decision.
"To continue until 2017, it's been amazing. London is where it all happened. It changed my life and my career," said the four-time Olympic champion, who will race at Birmingham's Diamond League meet next weekend.
"No matter what I do in life, it will never be the same. I will sadly miss that. But it is time to make a move. I want to be able to close that chapter in my life. I've done my country and many people proud. It makes me proud to be British.
"For many years... growing up in Teddington and seeing the Kenyans and Ethiopians winning I never thought, 'One day, we'll be able to challenge them and beat them at their own game'.
"You remember Haile Gebrselassie, Paul Tergat, they were winning for many years. Nobody would have thought a British guy would ever beat the Kenyans and Ethiopians.
"I'm very proud to have achieved what I have achieved. It's been an incredible journey. I hope I can leave a legacy behind for the younger kids and show anything is possible in life if you stick at it.
"Sometimes, I get emotional because track is where I've made it. I won obviously at London 2012. The following week, when the Olympics had finished, I was known worldwide."
Farah insisted he has no intention of returning to the track but admitted he needed a wake-up call about possible retirement at the Great Edinburgh Cross Country in January after finishing seventh.
"I honestly thought there was a point in my life where, in January, I mentally wasn't ready. I was training at home, just enjoying life and other stuff," he said.
"Edinburgh gave me a wake-up call over 'Do I want to be an athlete and carry on?', because I wasn't ready for that race. I knew it was going to take a block of high extra training.
"Do I wake up and go, 'I'll give it one more year on the track'? And that's what I did. I gave it everything I could. That's part of me.
"But now the track is finished. I don't like to keep still. I want to continue on. I like the pain and the challenges of being an athlete.
"I think can do something on the road. But I think it will take a few years and few marathons to get it right."