Hailemaryam Kiros first appeared on the international stage as a junior, winning a silver medal in the steeplechase at the African U18 Championships in 2013. That early versatility eventually gave way to a focus on road running. By 2020, he had earned selection for Ethiopia's team at the World Half Marathon Championships in Gdynia after winning the national trial race. His marathon career moved in steady increments. He ran 2:04:41 at the 2021 Paris Marathon for second place. By 2024, he was close at the biggest races: fourth at the Tokyo Marathon and fifth at the Berlin Marathon in a personal best 2:04:35. Those near-misses built toward his breakthrough in 2025, a commanding victory at the TCS Sydney Marathon in 2:06:06. He set a course record and produced the fastest marathon time ever run on Australian soil. The race was Sydney's inaugural edition as an Abbott World Marathon Major, making Kiros the first men's champion in the event's new era.