Jane Jacobs’s The Death and Life of Great American Cities (1961) had an enormous influence on urban design theories and practices. This study aims to operationalize Jacobs’s conditions for a vital urban life. These are (1) mixed use, (2) small blocks, (3) aged buildings, and (4) a sufficient concentration of buildings. Jacobs suggested that a vital urban life could be sustained by an urban realm that promotes pedestrian activity for various purposes at various times. Employing multilevel binomial models, we empirically verified that Jacobs’s conditions for urban diversity play a significant role with regard to pedestrian activity.