The fourth child in a family of nine, he took up the javelin at secondary school when he realized he wasn't going to be a successful footballer.
"My first-born sister used to encourage me, my mum also, but my dad sometimes was angry with me," Yego said.
"Most of my time I was going out of school, no learning, so he was a bit angry with me. But after I proved him wrong he let me continue with this sport."
Yego briefly dabbled with the track, but at a stocky 85 kg his physique is more suited to an event like the javelin and its incredible technical demands.
It helped that an elder brother was also a javelin thrower at their elementary school, and he was also inspired by watching the 2004 Athens Games on the television.
"It just took me, I wanted to be like Andreas Thorkildsen," he said.
Little could he have realized that eight years later, Yego would be competing against his hero in an Olympic final.
With no specialist javelin coaches in Kenya, the then teenager turned to technology to see what Thorkildsen and other great champions such as Czech Jan Zelezny were doing.
"I watched YouTube and it really paid off for me, to see the training techniques and skills they are using," he said.
Yego first made his mark with third place at the 2010 African championships in Kenya's capital of Nairobi, but disappointment followed at the Commonwealth Games in New Delhi later that year as he was well below his best in finishing seventh.