[6] Hagos noted that his first national selection had helped him develop his running and he went on to win the junior title at the Ethiopian Club's Cross Country, competing for Mesfin Engineering.

He made his debut on American soil at the Boston Indoor Games, taking fourth place in a best of 7:44.08 minutes for the 3000 m.[4] Still 17 years old, he was runner-up to World medallist Dejen Gebremeskel at the Carlsbad 5,000.

[10] He entered his first 5,000 m Diamond League event at the Shanghai Golden Grand Prix in May and upset the field by winning in wet conditions, setting a meet record time of 13:11.00 minutes and beating athletes including Kenenisa Bekele and Augustine Choge.

[11] In February 2013, Gebrhiwet set a new junior world record in the 3000 m by winning the New Balance Indoor Grand Prix, beating Dejen Gebremeskel and Galen Rupp with a time of 7:32.87.

At the 2013 World Championships in Athletics in Moscow, Gebrhiwet won the silver medal in the 5,000 m. He leaned at the finish line to beat Kenyan Isaiah Koech, and both were timed at 13:27.26.