A Hard Day Original Soundtrack
| Composed by | Mok Young Jin |
| Published by | Mirrorball Music |
| Release type | Film Score - Official Release |
| Format | 1 Digital - 20 tracks |
| Release date | June 09, 2014 |
| Duration | 00:45:37 |
| Genres |
| 1 | A Hard Day IntroMok Young Jin | 00:46 |  |
| 2 | A Perfect DayMok Young Jin | 01:12 | |
| 3 | Internal AffairMok Young Jin | 00:42 | |
| 4 | Inspection PointMok Young Jin | 02:03 | |
| 5 | Hide It !Mok Young Jin | 06:15 | |
| 6 | A CriminalMok Young Jin | 01:34 | |
| 7 | Back To the PlaceMok Young Jin | 01:25 | |
| 8 | A Mysterious CallMok Young Jin | 03:48 | |
| 9 | Taxi ChaseMok Young Jin | 03:13 | |
| 10 | Bad DreamMok Young Jin | 01:25 | |
| 11 | Drug BusinessMok Young Jin | 01:42 | |
| 12 | Here I GoMok Young Jin | 01:07 | |
| 13 | Hold Up!Mok Young Jin | 01:24 | |
| 14 | Cold HeartMok Young Jin | 01:58 | |
| 15 | Payback TimeMok Young Jin | 01:03 | |
| 16 | Time BombMok Young Jin | 01:08 | |
| 17 | The LakeMok Young Jin | 02:37 | |
| 18 | SurpriseMok Young Jin | 07:44 | |
| 19 | DriveMok Young Jin | 01:27 | |
| 20 | A Hard Day Ending CreditMok Young Jin | 03:04 | |
