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 | 13 | 9 | 2 | 2 | 31 | 16 | 15 | 29 |
| 2 | Birmingham CityBirmingham | 12 | 9 | 2 | 1 | 23 | 11 | 12 | 29 |
| 3 | Wrexham | 13 | 7 | 4 | 2 | 21 | 10 | 11 | 25 |
| 4 | Barnsley | 14 | 7 | 4 | 3 | 23 | 18 | 5 | 25 |
| 5 | Mansfield TownMansfield | 12 | 7 | 3 | 2 | 20 | 14 | 6 | 24 |
| 6 | Lincoln CityLincoln | 13 | 7 | 3 | 3 | 20 | 16 | 4 | 24 |
| 7 | Bolton WanderersBolton | 13 | 7 | 2 | 4 | 22 | 19 | 3 | 23 |
| 8 | Huddersfield TownHuddersfield | 13 | 7 | 1 | 5 | 19 | 12 | 7 | 22 |
| 9 | Reading | 13 | 7 | 1 | 5 | 21 | 20 | 1 | 22 |
| 10 | Stockport CountyStockport | 14 | 5 | 6 | 3 | 20 | 17 | 3 | 21 |
| 11 | Exeter CityExeter | 12 | 6 | 1 | 5 | 13 | 10 | 3 | 19 |
| 12 | Charlton AthleticCharlton | 13 | 5 | 4 | 4 | 15 | 14 | 1 | 19 |
| 13 | Peterborough UnitedPeterborough | 14 | 5 | 3 | 6 | 25 | 26 | -1 | 18 |
| 14 | Rotherham UnitedRotherham | 15 | 4 | 5 | 6 | 14 | 18 | -4 | 17 |
| 15 | Stevenage | 14 | 5 | 2 | 7 | 10 | 15 | -5 | 17 |
| 16 | Blackpool | 13 | 4 | 4 | 5 | 21 | 25 | -4 | 16 |
| 17 | Bristol Rovers | 13 | 5 | 1 | 7 | 15 | 20 | -5 | 16 |
| 18 | Northampton TownNorthampton | 13 | 4 | 3 | 6 | 17 | 20 | -3 | 15 |
| 19 | Wigan AthleticWigan | 13 | 3 | 5 | 5 | 12 | 11 | 1 | 14 |
| 20 | Leyton Orient | 13 | 3 | 2 | 8 | 11 | 18 | -7 | 11 |
| 21 | Crawley TownCrawley | 14 | 3 | 2 | 9 | 12 | 25 | -13 | 11 |
| 22 | Cambridge UnitedCambridge | 12 | 3 | 1 | 8 | 11 | 17 | -6 | 10 |
| 23 | Shrewsbury TownShrewsbury | 14 | 2 | 2 | 10 | 13 | 25 | -12 | 8 |
| 24 | Burton Albion | 13 | 0 | 5 | 8 | 13 | 25 | -12 | 5 |
| > League One Full Table | |||||||||
