The 29-year-old, who began his professional career at Fratton Park, returned to the South Coast in January of this year.
He has since made eight appearances for Pompey and following the extension, he will now spend the last six matches of the campaign with the club.
Cooper joined Crawley from Bournemouth in the summer of 2012.
Restore Data
| Team | P | W | D | L | F | A | GD | PTS | |
| 1 | Wycombe WanderersWycombe | 16 | 12 | 2 | 2 | 36 | 18 | 18 | 38 |
| 2 | Wrexham | 17 | 10 | 4 | 3 | 26 | 11 | 15 | 34 |
| 3 | Birmingham CityBirmingham | 15 | 10 | 3 | 2 | 28 | 15 | 13 | 33 |
| 4 | Stockport CountyStockport | 17 | 8 | 6 | 3 | 29 | 17 | 12 | 30 |
| 5 | Huddersfield TownHuddersfield | 16 | 9 | 2 | 5 | 25 | 15 | 10 | 29 |
| 6 | Barnsley | 17 | 7 | 6 | 4 | 26 | 22 | 4 | 27 |
| 7 | Reading | 16 | 8 | 3 | 5 | 26 | 24 | 2 | 27 |
| 8 | Bolton WanderersBolton | 16 | 8 | 3 | 5 | 25 | 26 | -1 | 27 |
| 9 | Lincoln CityLincoln | 17 | 7 | 5 | 5 | 23 | 21 | 2 | 26 |
| 10 | Mansfield TownMansfield | 15 | 7 | 3 | 5 | 20 | 17 | 3 | 24 |
| 11 | Exeter CityExeter | 16 | 7 | 2 | 7 | 14 | 15 | -1 | 23 |
| 12 | Charlton AthleticCharlton | 16 | 6 | 4 | 6 | 17 | 17 | 0 | 22 |
| 13 | Peterborough UnitedPeterborough | 16 | 6 | 3 | 7 | 32 | 29 | 3 | 21 |
| 14 | Bristol Rovers | 17 | 6 | 3 | 8 | 17 | 23 | -6 | 21 |
| 15 | Wigan AthleticWigan | 16 | 5 | 5 | 6 | 15 | 13 | 2 | 20 |
| 16 | Blackpool | 17 | 5 | 5 | 7 | 24 | 30 | -6 | 20 |
| 17 | Stevenage | 16 | 5 | 4 | 7 | 11 | 16 | -5 | 19 |
| 18 | Northampton TownNorthampton | 17 | 4 | 6 | 7 | 19 | 23 | -4 | 18 |
| 19 | Rotherham UnitedRotherham | 16 | 4 | 5 | 7 | 14 | 19 | -5 | 17 |
| 20 | Crawley TownCrawley | 17 | 4 | 4 | 9 | 15 | 27 | -12 | 16 |
| 21 | Leyton Orient | 16 | 4 | 3 | 9 | 14 | 20 | -6 | 15 |
| 22 | Cambridge UnitedCambridge | 16 | 3 | 4 | 9 | 14 | 25 | -11 | 13 |
| 23 | Shrewsbury TownShrewsbury | 16 | 3 | 2 | 11 | 16 | 29 | -13 | 11 |
| 24 | Burton Albion | 16 | 1 | 5 | 10 | 15 | 29 | -14 | 8 |
| > League One Full Table | |||||||||
