Grabarz finished twelfth at the 2006 World Junior Championships and competed at the 2011 European Indoor Championships, finishing 23rd and failing to reach the final. Grabarz subsequently failed to qualify for the 2011 World Championships in Athletics and lost his National Lottery funding. After this string of poor performances and funding loss, Grabarz "realised I didn't want that disappointment to happen again and I realised it was my decision to make it not happen again." He moved to Birmingham to train and "make a fresh start so I could give 100% of what I have to offer." He secured financial help from the Ron Pickering Memorial Fund and BackleyBlack, the company run by former athletes Steve Backley and Roger Black. His coach Fuzz Ahmed commented: "If I hadn't found him backing and if he didn't have a credit card, I would have funded him, because that's how much I believed in him. I recognised he had matured into a person that wanted to be a world class high jumper, rather than somebody who was just a very good high jumper." 2012 saw a much improved Grabarz. In January 2012 he made his international breakthrough by jumping 2.34 metres at an indoor high jump gala in Wuppertal. His previous best was 2.28m and the jump saw him pass the Olympic 'A' qualifying standard. In June, Grabarz won gold at the European Athletics Championships with a jump of 2.31m. He followed this up at the 2012 London Olympics in August, by clearing 2.29 metres in the final to win a bronze medal. After victories in the Rome and Birmingham Diamond League events, Grabarz took the overall 2012 IAAF Diamond League high jump crown, winning the Diamond Trophy and $40,000 prize money. His personal best jump is 2.37 metres, a mark set at the Lausanne Diamond League meeting on 23 August 2012, equalling the British men's outdoor record held by Steve Smith since 1992. Grabarz finished joint fourth at the 2016 Olympics. He cleared a season's best height of 2.33 metres, the same height as bronze medallist Bohdan Bondarenko, at the first attempt but earlier in the competition he had failed at his first attempt at 2.25 metres, meaning that Bondarenko won the bronze on countback. In May 2018 he announced his retirement, because he doesn't enjoy the competitions anymore.
