Bull became the youngest Australian to climb Ama Dablam in the Himalayas, doing so at the age of 23. During his career, he has also been the first to ascend many unclimbed peaks. Between 2006 and 2017, Bull climbed the highest mountains and volcanic summits on each of the seven continents. He was 36 years old when he completed the challenge. He was also the first Australian to accomplish the feat.