An orientational distribution function is employed for the first time to describe segmental orientation in a uniaxially deformed network. The model assumes that each chain expands between two active junctions that displace affinely with the macroscopic deformation. The model was first introduced by Erman et al. and used to evaluate the second-order Legendre polynomial of the segment orientation. This paper extends their model to compute the orientation factors of a single segment up to the eighth order, thereby enabling a more complete description of the orientational distribution to be estimated. As an application of these results to oriented crystallization of polymeric systems, an evaluation of the orientational distribution function for crystallites in a polyethylene film manufactured by a calendering method is presented. The resulting theoretical distribution of the crystallites is in good agreement with the experimental function measured by X-ray diffraction techniques. Furthermore, the small-angle light-scattering pattern under H-v polarization was estimated by assuming a rod to be an aggregation of cylindrical clusters oriented with a kinetically determined distribution. The calculated light-scattering patterns are also in good agreement with the observed ones.