Transportation infrastructure facilities and pedestrian/driver behaviors are associated with neighborhood characteristics and the built environment. However, the effects of neighborhood characteristics and the built environment on pedestrian injury severity are not well documented. To investigate and quantify the effects of neighborhood characteristics and built environment on pedestrian injury severity, a random parameters generalized ordered probit model with heterogeneity in means and variances was proposed to consider the ordinal nature of injury data and the issue of threshold and unobserved heterogeneity. A total of 3867 pedestrian-vehicle crashes that occurred in Florida Department of Transportation District 7 from 2011 to 2014 were analyzed. Based on the estimation results, three factors (African American community, school zone, and bus stop area) related to neighborhood characteristics and the built environment were identified to have significant influence on pedestrian injury severity. Pedestrian-vehicle crashes that occurred in African American community or bus stop area are less likely to involve incapacitating and fatal injuries. The presence of a school within a 0.5-km buffer from a crash leads to a decreased probability of fatal injury and an increased probability of incapacitating injury. In addition, the estimated parameter for elderly pedestrian indicator (50 < age ≤ 65) was found to be random with significant heterogeneity in both mean and variance (where the mean and variance are associated with intersection-related crash indicator). Compared to younger pedestrians (age ≤ 30), 74.3% of elderly pedestrians who are involved in intersection-related crashes are more likely to suffer severe injury (fatal or incapacitating injury), while 52.4% of elderly pedestrians who are not involved in intersection-related crashes are more likely to suffer severe injury.