American Ninja Warrior 3
Tim competed in the Venice Beach Qualifiers of American Ninja Warrior 3, scaling the Warped Wall with a time fast enough to advance to the Semi-Finals. In the Semi-Finals however, he shockingly fell on the Log Grip, an obstacle he had easily completed in the qualifiers. Due to this he was unable to advance to Boot Camp, ending his first season early. This is currently his earliest exit ever in a ninja competition.
American Ninja Warrior 4
Tim returned in American Ninja Warrior 4 and was the final runner of the Northeast Regional Qualifiers as well as the fastest runner in the region. He moved on to the City Finals and almost fell on the Bungee Bridge, but was able to complete the extended course with the fastest time, earning him a spot in Vegas. In the Las Vegas Finals he progressed through the obstacles well, but shockingly failed the 7th obstacle of the First Stage: the Spin Bridge. This was also Tim's last ninja competition competing as a non-Vegan athlete.
American Ninja Warrior 5
In American Ninja Warrior 5, Tim completed the Baltimore Qualifying Course in the 4th fastest time, advancing to the City Finals. There he performed well, before tiring on the Body Prop and dropping into the water below. However, he placed 10th in the finals overall, earning him a spot in Vegas once again. In Tim`s 2nd trip to Mt. Midoriyama, he cleared the Twelve Timbers, Giant Cycle and Rope Glider easily, but didn`t get a chance for redemption on the Spin Bridge when he shockingly failed the Jumping Spider. This would be his final season competing in a main American Ninja Warrior tournament, but not his final performance on the show overall...
USA vs. The World
Although Shieff didn't compete in American Ninja Warrior 6, he did compete and captain Team Europe in the USA vs. The World special as a representative for Great Britain. In the first stage, he blasted through the course, taking revenge on both the Jumping Spider and Spin Bridge and finishing with a record time of one minute and two seconds, defeating both Team USA's Elet Hall and Team Japan's Hitoshi Kanno in the process. In the Second Stage he cruised through the first four obstacles well, but grabbed the chain on the Metal Spin too low, causing him to fall into the water, beating Team Japan's Matachi Ryo who failed Rope Jungle, but losing the heat to Team USA's Travis Rosen who completed the stage. Despite this, Team Europe went on to win the event, although Tim did not attempt the third or final stages.
USA vs. The World 2
In the second USA vs. The World special, this time part of American Ninja Warrior 7 - filmed in 2015 and aired in early 2016 - Tim returned once again to captain Team Europe and represent Great Britain, although this time he was joined by fellow Ninja Warrior UK competitor: Tim Champion. He once again ran the First and Second Stages, clearing the upgraded First Stage in a blistering one minute and twenty-five seconds, although unfortunately this time was not fast enough to defeat Team USA's Drew Drechsel, who cleared the stage in one minute and eighteen seconds, even though he did defeat Team Japan's Morimoto Yusuke, who failed the Jumping Spider. However in the Second Stage, Tim placed last in his heat, failing the Unstable Bridge behind Team Japan's Tomohiro Kawaguchi (Roulette Row) and, once again, Drew Drechsel, who cleared the stage. Team Europe went on to place 2nd overall, losing to Team USA by two points.
USA vs. The World 3
Tim has been confirmed to compete in the third USA vs. The World competition (part of American Ninja Warrior 8), once again as part of Team Europe. Many anticipated him to blaze through Stage 1 after many previous times doing so, but Shieff was shown to have a knee injury. He was instead replaced by Bjarke Tonessen during the competition, and instead coached his other teammates from Europe on running the obstacles.
Ninja Warrior UK 1
Due to his dual-citizenship between the USA and UK, Tim was able to compete in the first season of Ninja Warrior UK. During the competition he performed well, fighting through both the heats and semi-finals with ease and advancing to the final. In the final his streak of strong performances continued. He was able to clear the First Stage, taking revenge on both the Jumping Spider and Spin Bridge once again. In the Second Stage he completed obstacles such as the Salmon Ladder and Unstable Bridge easily, advancing farther than anyone else but ultimately timing out on the third wall of Wall Lift, less than a second away from the buzzer, earning him the title of Last Man Standing.
Ninja Warrior UK 2
Returning from his incredibly strong performance in the first season, Shieff returned for the second Ninja Warrior UK tournament, hoping to replicate his success. In the heats he once again performed well, but later failed the 8th obstacle of the semi-finals: The Arm Rings. Despite this, he progressed far enough, fast enough to qualify for the Finals. In the Finals he became one of only five athletes to clear the deadly Paddle Boards, and one of only three to clear the First Stage that season. In the Second Stage he moved quickly, and was on track to clear before he reached the Salmon Ladder. There, despite reaching the top of the ladder, the bar slipped backwards off the rungs during his transition to the Unstable Bridge, ending his run with a course out. Despite this, he still earned the title of Runner-Up for the second season of Ninja Warrior UK.