James McGrath is an American, who has competed five times in the American Ninja Warrior tournaments. In his first attempt, on American Ninja Warrior 2, his run ended early, when he failed on the Quad Steps.

On American Ninja Warrior 3, he was a walk on competitor from Seattle, WA who slept in a van to be a walk-on. In that competition he placed 29th in the Qualifying Round and 13th in the Semis. He did very well in Boot Camp and that earned him a spot in SASUKE 27. In the tournament, he was able to blitz through the first two stages with little trouble, completing Stage 1 in with 22.24 seconds to spare and had SASUKE 27's fastest Stage 2 time with 18.84 seconds left on the clock. However, he ultimately failed on the Ultimate Cliffhanger after failing the transition to the small fifth ledge.

He also competed on American Ninja Warrior 4 and was one of the favorites to earn total victory. He had the 2nd fastest time in the Northwest Regional Qualifiers, and the fastest time in the Northwest Regional Finals, giving him a late run in the Las Vegas Finals. He easily beat Stage 1 with just under 19 seconds to spare, making him of the 24 finalists to advance to Stage 2. However, his downfall came at Stage 2, where he suprisingly failed on the Slider Drop by making the bad choice of jumping before the drop, shifting his weight to one side and not landing the left side.

In American Ninja Warrior 5, McGrath completed the Venice Beach Finalists with the fastest time and he cleared the First Stage in the Las Vegas finals with 38.47 seconds left. In the second stage, he blazed through all the obstacles and finished with the second fastest time on the stage with 35.66 seconds left on the clock. On the third stage, however, he wasn't able to hang on while transitioning to the second board on the Floating Boards and failed.

In American Ninja Warrior: USA VS Japan, James was apart of team America. In the first stage, he went up against Yamamoto Shingo, and he beat him when he couldn't make it up the Soritatsu Kabe. Then, in the second stage, he went up against Asa Kazuma, he beat him as well, as he failed the Double Salmon Ladder and James did a victory lap on the stage. In the third stage, James went up against Urushihara Yuuji, where he went out on the Floating Boards again, but Yuuji also went on the same obstacle and James won the match barely by beating him to the second board by a few seconds. He was the only competitor to attempt all three stages.

So far, in American Ninja Warrior 6, he has completed the qualifying round in the second-fastest time. In the Venice Finals, he failed the Body Prop but still finished in the Top 15, qualifying him for the Las Vegas Finals.