In his debut in American Ninja Warrior 5, he impressively managed to defeat the Circle Cross that took out his brother to make it to Vegas. He later went on to complete the qualifying course and place 12th overall.
In the city finals, he once again dominated, beating the finals course and placing 3rd at the end of the Baltimore finals. This earned him his first trip to Las Vegas.
In Vegas, however, he shocked everyone when his foot slipped on the Timbers, the first obstacle on Stage 1, and failed.
He returned in American Ninja Warrior 6 and managed to make it to Vegas for the second time after finishing in 15th in the St. Louis qualifiers and 7th at the St. Louis finals. His brother Chris also got into the Vegas finals, making this season the only one thus far that both Wilczewski brothers competed together at Mt. Midoriyama.
In Vegas, Brian made it further than last time, but he got careless and slipped on the Spider Walk portion of the Jumping Spider. His fall was notably similar to Isaac Caldiero's in the previous season.
Similar to his debut in American Ninja Warrior 5, he competed in American Ninja Warrior 7 and finished the qualifying course in Pittsburgh, while his older brother Chris failed qualifying. He made it to the Pittsburgh finals finishing with the 10th fastest time, and made it to the Floating Monkey Bars in the city finals, where he was one of the many to fall on it. Wilczewski had eventually placed 9th overall and made it to Vegas for the third time in his career.
He didn't compete in American Ninja Warrior 8, despite how he did in the previous tournament, but he was shown cheering on his brother, Chris Wilczewski. However, he returned in American Ninja Warrior 9, competing in Los Angeles this time. His run was all cut from the broadcast, but he managed to finish the qualifying course with the fourth fastest time.
In the city finals, Brian fell on the Stair Hopper, an obstacle his brother completed in the previous season, due to him putting too much aggression on the bar, causing it to peel his hands off. Despite this, he still advanced to the national finals placing 7th.
In Las Vegas, in a similar fashion to his first trip to Vegas, he shocked everyone failing Snake Run, the first obstacle of Stage 1, by trying to jump for the second step.
Brian did not compete in American Ninja Warrior 10. Just like season 8, however, he was shown on the sidelines cheering on his brother, Chris.
Team Ninja Warrior
He competed on the new Team Ninja Warrior spin-off with his brother Chris and Michelle Warnky. His team name is confirmed to be the "Lab Rats", as the three of them work for the Movement Lab in Ohio. Their team just barely missed out on the championship relay, being beaten by Brian Arnold's team, Party Time.
- With Brian failing the Roulette Row on American Ninja Warrior 7, the fifth obstacle on Stage Two proved to be his best season to date.
- Brian and Chris both attempted the Stair Hopper, with Chris completing it on American Ninja Warrior 8 and Brian failing it in the next season.
- It was erroneously commentated in American Ninja Warrior 9 that Brian was the only competitor to fail the Timbers. In reality, there were actually four competitors to fail it in that season, counting him.
|5||72||Failed Timbers (First Stage)|
|6||68||Failed Jumping Spider (First Stage)||Spider Walk portion.|
|7||Failed Roulette Row (Second Stage)||Digest|
|9||7||Failed Snake Run (First Stage)|