Harmes was raised in Devon Meadows, Victoria and attended both Hillcrest Christian College and Hallam Senior College for secondary school. He played his junior football with the Devon Meadows Football Club, including eight senior games when he was sixteen years of age. He was recruited by the Dandenong Stingrays in 2012 to play in the TAC Cup as a bottom-aged player and played six games for the season. He received mid-year state honours in 2013 by representing VictoriaCountry at the AFL Under 18 Championships and played two matches. He spent the majority of his final junior year playing for the Dandenong Stingrays, including the grand final loss to the Eastern Ranges, in addition he received the most determined award.
AFL career
Barracking for the Melbourne Football Club as a youngster, Harmes was drafted by them with their first selection and second overall in the 2014 rookie draft. In 2014, he spent the season playing in the Victoria Football League for Melbourne's affiliate team, the Casey Scorpions; he punctured his lung in the middle of the season which left him injured for six weeks. After playing with the Casey Scorpions for the first half of 2015, he was promoted to Melbourne's senior list in July, replacing the injured Jack Trengove, and he made his AFL debut in the nine point loss against at the Melbourne Cricket Ground in round 15. He played eight out of the nine remaining matches for the season after being rested for the round 22 match against at Domain Stadium. In the final round match against at Etihad Stadium, he received praise from the head of football writer at the Herald Sun, Mark Robinson, for his tenacity and contested play. After two seasons on the rookie list, he was promoted to the senior list in November. After playing every pre-season match in the 2016 NAB Challenge, Harmes started the season playing in the AFL when he played in the two-point win against Greater Western Sydney at the Melbourne Cricket Ground in round one. Stating that he plays his best football when he wins contested possessions, he was named the round seven Rising Star nominee in the seventy-three point win against, where he recorded twenty-six disposals — eleven of which were contested — three goals, and five tackles. He missed his first match for the season when he was omitted for the Queen's Birthday clash against in round twelve. He returned to the side for the twenty-two point loss against at the Melbourne Cricket Ground in round fifteen. He missed only one match for the remainder of the season, the round twenty-two match against at the Melbourne Cricket Ground to finish with nineteen matches for the season and place nineteenth overall in the club best and fairest count.
