In 2000 Midtbø started climbing when he was 11 years old after his mother signed him up for a climbing course. After only one year of climbing he won the Norwegian Youth Championship. And one year later in 2002 he on-sight climbed his first lead route Øgletryne at the Sageveggen rock wall near Bergen. In 2005 he won the World Youth Championships in Beijing, China. Midtbø moved to Innsbruck in 2007 after finishing high school. At the time Innsbruck was a place where many top international climbers were training together for competitions, such as David Lama, Jakob Schubert and Anna Stöhr. In an interview Midtbø described David Lama as the most talented person he had ever climbed with, a climber he looked up to at the time. In August 2010, he made his hardest ascent to date, when he sent the route Ali Hulk sit start extension in Rodellar in Spain. The route is a boulder and a sport climbing route linked together. The first ascent was made by Daniel Andrada in 2007. The grade is and at 2013 there were only six climbers who had climbed routes at this level in the world. In an interview with UK Climbing, Midtbø stated that there were many difficulties with this climb, including resting in the first boulder part for working the rest of the route, and the strain on the core because it is overhanging. In May 2013, Midtbø on-sighted the route Cosi fan tutte at Rodellar in Spain., only four other people had on-sighted at the 8c+ level or higher: Patxi Usobiaga, Adam Ondra, Ramon Julian Puigblanque, and Alex Megos. Midtbø retired from competition in May of 2017. On the 95th Vlog of Midtbø's Youtube channel, he described his decision to retire as follows, "I still get motivated just by climbing, I think some people need a specific goal, but I’ve never felt like I needed one. It sounds really cheesy I know, I just love climbing I love being in the nature, I love the feeling of feeling free, but it is like that you know. I don’t know, I like the lifestyle, I like traveling, I like trying hard, and most of all, I like the feeling of feeling really fit, really strong, the feeling of being able to climb anything."
Midtbø runs a successful eponymous Youtube channel which, as of January 2020, has over 547,000 subscribers. On his channel, Midtbø posts videos centered around climbing with themes including training advice, collaboration with other climbers, and otherwise display of Midtbø's own skill. The majority of his videos are part of his vlog series, which he has consistently posted since March of 2017. He also posts climbing and workout related pictures and videos on his Instagram, where he has more than 615k followers.
Trivia
His sister Hannah Midtbø is also a professional climber. She won the nordic championships in category lead in 2006 and participated in various IFSC bouldering worldcups and European Championships. In 2013 Midtbø participated in a German TV show called Der Deutsche Meister as the international contender in the category Reckstangenklettern. Midtbø won against the German contender. In January 2020, Midtbø represented Team Europe in.
Controversy
Midtbø garnered negative media attention in 2016 after publishing an Instagram picture of himself hanging off the Trolltunga rock formation, a popular tourist attraction in Norway. Midtbø suspended himself from the overhanging rock wearing a safety harness, but local police officers were concerned that the stunt might encourage people without proper protection to risk their lives.
