Obermueller attended City High in Iowa. He ended senior year with a 7-1 record with 103 strikeouts in 50.1 innings, 0.89 WHIP and 1.11 ERA. He was ranked the no. 1 LHP in Iowa by Perfect Game, and the no. 10 player in Iowa by Prep Baseball Report. He chose to join the Iowa Hawkeyes following his high school career.
Last season as a freshman, Obermueller pitched mostly out of the bullpen, making 15 appearances and just 2 starts. He finished the year with a 4.91 ERA, striking out 36 batters and walking 19 in 22.0 innings. He had a 2-1 record on the year and recorded 1 save as well. He was used in many ways and many situations on the mound in a productive first season.
This year is Obermueller's sophomore year and he will be draft eligible following the season. He is expected to take over a starting role for the Hawkeyes this season.