A rain delay impacted running initially at the Iowa Speedway, which resulted in the Xfinity Series qualifying session being cancelled.
The rain knocked the qualifying session down from two rounds to one, leaving no room for error.
Larson: Everyone looked really on edge
Larson was the last driver to take to the short 0.875mile oval track and as such he was able to bag the top spot ahead of the inaugural race in Iowa.
Speaking to NBC Sports after securing pole, Larson said: “It was challenging for sure, it wasn’t as challenging as I was expecting. I got to watch everybody, everybody looked really loose, really on edge, I just tried to be under the edge a little bit.
“My lap felt fairly smooth, a little bit edgy, not as bad as I was expecting. It helps going out last. It helps being able to watch everybody. I get to talk to Cliff [Daniels] before I go out to is beneficial”
Ryan Blaney, Josh Berry, William Byron and Brad Keselowski completed the top five, from second to fifth respectively.
Blaney and Berry were within a shout to secure pole position as the former missed out by 0.025s, and the latter was just under a tenth from Blaney.
Chase Briscoe, Kyle Busch, Tyler Reddick, Chase Elliott and Christopher Bell completed the top 10 from sixth to 10th.