The men's 400 metre individual medley competition at the 2023 World Aquatics Championships was held on 23 July 2023.

Records Prior to the competition, the existing world and championship records were as follows.

The following new records were set during this competition. Date Event Name Nationality Time Record 23 July Final Léon Marchand 4:02.50 WR

Results Heats The heats were started at 12:52.

Rank Heat Lane Name Nationality Time Notes 1 2 4 Carson Foster 4:09.83 Q 2 3 4 Léon Marchand 4:10.88 Q 3 2 5 Daiya Seto 4:10.89 Q 4 2 6 Alberto Razzetti 4:11.57 Q 5 2 3 Brendon Smith 4:11.75 Q 6 3 5 Chase Kalisz 4:12.37 Q 7 3 2 Balázs Holló 4:12.77 Q 8 3 3 Lewis Clareburt 4:12.85 Q 9 2 1 Lorne Wigginton 4:13.75 10 3 7 Apostolos Papastamos 4:14.52 11 2 7 Thomas Neill 4:14.98 12 2 8 Thomas Jansen 4:16.00 13 3 0 Collyn Gagne 4:16.08 14 3 6 Tomoru Honda 4:16.71 15 1 2 Erik Gordillo 4:20.17 16 3 8 Stephan Steverink 4:21.22 17 1 6 Marius Toscan 4:21.24 18 1 5 Héctor Ruvalcaba 4:21.25 19 2 0 Ádám Telegdy 4:21.29 20 3 1 Luan Grobbelaar 4:21.54 21 2 9 Kim Min-suk 4:22.17 22 3 9 Richard Nagy 4:22.96 23 1 3 Nguyễn Quang Thuấn 4:25.92 24 1 7 Tan Khai Xin 4:26.83 25 1 8 Jarod Arroyo 4:27.11 26 1 1 Munzer Kabbara 4:28.66 27 1 9 Kristaps Mikelsons 4:36.22 1 0 Fu Kun-ming 2 2 Wang Shun 1 4 Jaouad Syoud

Final The final was started at 21:21.

Rank Lane Name Nationality Time Notes 5 Léon Marchand 4:02.50 WR 4 Carson Foster 4:06.56 3 Daiya Seto 4:09.41 4 7 Chase Kalisz 4:10.23 5 2 Brendon Smith 4:10.37 6 8 Lewis Clareburt 4:11.29 7 6 Alberto Razzetti 4:11.73 8 1 Balázs Holló 4:13.36

References