The picture won best feature, breakthrough director for Fleck and breakthrough actor for Shareeka Epps, who tied with Babel's Rinko Kikuchi. Half Nelson was released earlier this year in North American through THINKFilm.
Alejandro Gonzalez Inarritu's Babel also won best ensemble acting honours for Brad Pitt, Cate Blanchett, Gael Garcia Bernal, Koji Yakusho, Adriana Barraza, Rinko Kikuchi, Said Tarchani, and Boubker Ait El Caid.
James Longley's Iraq In Fragments won best documentary, and Choking Man directed by Steve Barron won the Best Film Not Playing At A Theater Near You Award. Iraq In Fragments is a Typecast Releasing in association with HBO Documentary Films.
'With only six competitive awards, each award carries a significant amount of prominence,' IFP executive director Michelle Byrd said. 'Our juries had amazingly passionate conversations and I think their selection reflects a diverse range of talent and films with strong points of view.'
As previously announced, Gotham Awards Tribute went to Kate Winslet, Edward Norton, Todd Wagner and Mark Cuban, Ellen Kuras, Alfonso Cuaron, Guillermo del Toro and Alejandro Gonzalez Inarritu, and Tim Robbins.
16th Annual Gotham Awards winners:
Best feature: Half Nelson (THINKFilm)
Dir: Ryan Fleck; Prdrs: Jamie Patricof, Alex Orlovsky, Lynette Howell, Anna Boden, and Rosanne Korenberg
Best documentary: Iraq In Fragments (Typecast Releasing in association with HBO Documentary Films)
Dir: James Longley; Prdrs: James Longley and John Sinno
Breakthrough Director Award: Ryan Fleck for Half Nelson
Breakthrough Actor Award: Shareeka Epps for Half Nelson and Rinko Kikuchi for Babel (Paramount Vantage)
Best Ensemble Cast Award: Babel (Brad Pitt, Cate Blanchett, Gael Garcia Bernal, Koji Yakusho, Adriana Barraza, Rinko Kikuchi, Said Tarchani, and Boubker Ait El Caid)
Best Film Not Playing At A Theater Near You Award: Choking Man
Dir: Steve Barron; Prdrs: Joshua Zeman and Zachary Mortensen