Alpha Dog is a 2006 American crime drama film directed by Nick Cassavetes and written by Nick Cassavetes, J.T. Ruddy, and David McKenna. The film is based on the true story of the kidnapping and murder of 15-year-old Nicholas Markowitz in 2000.
The font used for the Alpha Dog title in the poster seems to be Madison Regular, a slab serif stencil typeface by MadType. More details about it can be found here.