Aman was the inaugural winner of the
1000 metres race at the
2010 Youth Olympics in Singapore. He won a
silver medal in the
800 m at the
2011 World Youth Championships in Athletics, coming in secong behind
Leonard Kirwa Kosencha who set a world youth record. He ran an
Ethiopian record to win his semi-final heat at the
2011 World Championships in Athletics, but finished last in the event final. In September he improved his Ethiopian record to 1:43.37 behind
David Rudisha at the
Rieti Meeting, then ended Rudisha's 34-meet winning streak at the
Notturna di Milano, beating him by seven hundredths of a second in a time of 1:43.50. Aman's time stood as a world under-18 record until 2025, when
Cooper Lutkenhaus ran 1:42.27. He won 800 m final in the
2012 IAAF World Indoor Championships in Istanbul as the youngest gold medalist athlete. He finished 6th in the 800 metres at the
2017 World Championships held in London. ==Competition record==