The Values in Action Inventory of Strengths (VIA-IS) is a widely-used measure for character. Its factorial structure is still debated, however, and previous validation studies usually failed to examine the unidimensionality of the single character strengths. In addition, no studies to date have examined its Italian version. We validated the structure of the Italian short form of the VIA-IS in a sample of 16722 participants. Using confirmatory factor analysis and treating items as ordinal variables, we followed three simple, but too often neglected, steps: we studied the unidimensionality of the single strengths first, then their convergence into second-order virtues, and then fitted a hierarchical model that includes items, strengths and virtues, as originally proposed by Peterson and Seligman. All strengths except "love of learning" were unidimensional, and both the virtues and the final hierarchical models showed acceptable fit indices, unlike three models derived from an exploratory factor analysis. The same findings emerged for a smaller sample of 1035 participants. Finally, both character strengths and virtues showed positive relations with general mental health and negative relations with psychological distress. These results are discussed considering previous studies on the factorial structure of the VIA-IS.