| ITF USA F18 | 06/27 18:00 | 25 | Hernandez Serrano, Juan Alejandro v Callahan, Hunter | 6-2,6-2 | |
| ITF USA F39 | 11/29 16:00 | 26 | [440] Callahan, Hunter v Shane, Ryan [463] | 6-7,2-6 | |
| ITF USA F39 | 11/28 15:30 | 25 | Butler, Samm v Callahan, Hunter | 4-6,4-6 | |
| ITF USA F38 | 11/23 15:00 | 26 | [429] Callahan, Hunter v Sarkissian, Alexander [255] | 2-6,5-7 | |
| ITF USA F38 | 11/21 18:40 | 25 | Vaghela, Vidit v Callahan, Hunter | 4-6,3-6 | |
| Challenger Champaign Qual | 11/12 17:00 | 46 | [181] Lawson, Alex v Callahan, Hunter [388] | 6-4,5-7,6-1 | |
| Challenger Champaign Qual | 11/11 20:25 | 45 | Callahan, Hunter v Pauffley, Neil | 7-6,6-2 | |
| ITF Thailand F9 | 10/18 03:00 | 26 | Yu, Cheng-Yu v Callahan, Hunter | 6-3,6-1 | |
| ITF Thailand F9 | 10/16 03:00 | 25 | Punnakrit Kritakara v Callahan, Hunter | 5-7,5-7 | |
| ITF Thailand F8 Qual | 10/08 05:50 | 44 | Callahan, Hunter v Kerdlaphee, Phongsapak | 3-6,7-5,5-7 | |
| ITF Thailand F7 | 10/03 02:45 | 25 | Takeuchi, Kento (1987) v Callahan, Hunter | 6-3,6-4 | |
| ITF USA F31 | 09/22 17:00 | 27 | Callahan, Hunter v Craig, Henry | 3-6,6-1,3-6 | |
| ITF USA F31 | 09/21 21:30 | 26 | Callahan, Hunter v Jacob Bullard | Retired | |
| ITF USA F31 | 09/19 17:00 | 25 | [423] Matias Franco Descotte v Callahan, Hunter [424] | 3-6,4-6 | |
| ITF USA F30 | 09/13 16:00 | 25 | Verboven, Laurens v Callahan, Hunter | 7-6,4-6,6-4 | |
| ITF Canada F5 | 08/31 18:30 | 26 | [428] Pavic, Ante v Callahan, Hunter [425] | 7-6,6-4 | |
| ITF Canada F5 | 08/29 17:55 | 25 | Callahan, Hunter v Day, Alexander | 6-4,6-3 | |
| ITF USA F27 | 08/12 14:30 | 28 | Ram-Harel, Or v Callahan, Hunter | 6-3,1-6,6-3 | |
| ITF USA F27 | 08/11 14:30 | 27 | Perez, Alfredo v Callahan, Hunter | 6-3,1-6,4-6 | |
| ITF USA F27 | 08/10 14:30 | 26 | Callahan, Hunter v Alex Rybakov | 7-5,7-5 | |
| ITF USA F27 | 08/08 18:10 | 25 | Callahan, Hunter v Johnson, Eric | 6-4,6-2 | |
| ITF USA F26 | 08/03 16:20 | 26 | Aziz Dougaz v Callahan, Hunter | 6-4,6-4 | |
| ITF USA F26 | 08/02 16:35 | 25 | Nguyen, David v Callahan, Hunter | 6-4,1-6,6-7 | |
| ITF USA F25 | 07/24 17:15 | 25 | Riffice, Sam v Callahan, Hunter | 7-5,6-3 | |
| ITF USA F24 | 07/18 21:40 | 25 | Harrison Adams v Callahan, Hunter | 6-3,5-7,6-3 | |
| ITF USA F22 | 06/29 14:00 | 26 | Callahan, Hunter v Gonzalo Lama | 6-4,6-7,4-6 | |
| ITF USA F22 | 06/28 14:00 | 25 | Strong Kirchheimer v Callahan, Hunter | 3-6,1-6 | |
| ITF USA F20 | 06/20 20:10 | 25 | Gonzalo Lama v Callahan, Hunter | 6-4,0-6,7-6 | |
| ITF USA F18 | 06/15 18:30 | 26 | Callahan, Hunter v Kaichi Uchida | 3-6,4-6 | |
| ITF USA F18 | 06/15 15:30 | - | Callahan, Hunter v Kaichi Uchida | 3-6,4-5 |