His breakthrough performance came in the Sheffield Shield final of 2014/15, where he was the Man of the Match, scoring 81 and 158 against Victoria at the Bellerive Oval. However, it failed to grab the attention of the selectors since it came in a stalemate, causing the opposition to win the title. His form went through a bit of a dip, and he had to leave Western Australia for Victoria before the start of the 2016/17 season of the Sheffield Shield, given the first-class average of 28.43 – an unflattering one for such a talented cricketer according to his then-coach Justin Langer, who would go on to coach him when he first received his Baggy Green in 2018.
The move to Victoria was a pivotal decision in the life of Marcus Harris. After a run-glut in the first phase of the Sheffield Shield season, a wounded Australian side called him up to play the home Test series against India, where he exhibited maturity and resistance becoming of a top-class Test opener. Now being coached by Justin Langer, his ex-coach in Shield cricket, Harris was a comfortable member in the Australian dressing room, donning the Baggy Green with dignity in the troubled times for Australian cricket.
The diminutive opener scored two fifties in his debut series but that wasn’t enough to save Australia the blushes. A workmanlike batter, Harris did learn the trade of batting the hard way as the Indian bowlers hardly gave anything away. His first fifty at Perth though helped Australia to lay a strong base for a series-leveling win. Later against the touring Lankans, Harris got off to starts before throwing his wicket away. Harris is a part of the 2019 touring Ashes team.