2020–2021

Before the season started, O'Toole claimed the U20 US National championship in freestyle.^[8]

A true freshman, O'Toole racked up a 9–0 record in dual meets during regular season, competing solely along the Mid-American Conference due to COVID-19 restrictions.^[9] After claiming the Conference title, O'Toole competed at the NCAA tournament, where after making the quarterfinals, he was knocked into consolations by eventual finalist and third-seeded Jake Wentzel from Pittsburgh.^[10] He then notably stunned second-ranked Anthony Valencia from ASU by technical fall and fifth-ranked Zach Hartman from Bucknell by major decision before claiming third-place with a win over tenth-seeded Travis Wittlake from the Oklahoma State University, becoming an All-American and closing out the year at 19–1.^[11]

Fresh as an All-American, O'Toole repeated as the U20 US National champion, and then claimed the U20 World Championship with a technical fall in the finale, notoriously pinning 2020 Olympian and 2019 U23 World Champion Turan Bayramov in the quarterfinals.^[6]

2021–2022

Back to folkstyle, O'Toole racked up a Southern Scuffle title as well as a 12–0 record in dual meets during regular season, before making his Big 12 Conference debut and claiming the title in the post-season.^[12] At the NCAA tournament, O'Toole, the second-seed, notably took out returning All-Americans Anthony Valencia and Cameron Amine to make the finals, where he was able to edge returning NCAA champion Shane Griffith to become the NCAA champion himself and close out the year undefeated at 25–0.^[13] After the season, he was named the Big 12 Wrestler of the Year.^[14]

2022–2023

The returning national champion, O'Toole won the Tiger Invite title and compiled a 9–1 dual meet record during regular season, with a lone loss to fellow U20 World and NCAA champion David Carr, who had bumped up from 157 pounds to 165 pounds since the previous season.^[15] In the post-season, he claimed runner-up honors at the Big 12 Championships, losing the rematch to Carr in the finals.^[16] At the NCAA championships, O'Toole notably defeated All-Americans Wyatt Sheets, Carson Kharchla and two-timer Cameron Amine to cruise to the finals, where he upset Carr by decision, becoming a two-time NCAA champion and winning the rubber-match between National champions.^[17]

Fresh off an NCAA championship, O'Toole switched to freestyle and made his senior-level debut at the US Open National Championships in April.^[18] After a 3–0 stint, O'Toole fell to three-time NCAA champion and returning national champion Jason Nolf in the semifinals, before winning his next two matches to claim third-place.^[19] In June, he was set to compete against fellow two-time NCAA champion Vincenzo Joseph for third-place in the US World Team Trials at Final X, though he earned a forfeit victory and was then named to the U23 US World Team.^[20][21]

At the U23 World Championships, O'Toole notably defeated returning U23 World medalist Vadym Kurylenko, U23 European finalist Krisztian Biro and U17 World medalist Imam Ganishov in the finals to become the U23 World champion.^[22]

2023–2024

Back to folkstyle, O'Toole won the Tiger Invite and went 12–0 in dual meets before becoming a two-time Big 12 champion, with a win in the finals over now three-time All-American David Carr to tie the series at 2–2.^[23] At the NCAA tournament, O'Toole, the top-seed, cruised to the semifinals with three back-to-back pins, where he was upset by Carr in a fifth match and fell into the consolation bracket.^[24] He then defeated his next two opponents to place third and become a four-time All-American, closing out the year at 24–1.^[25]