Currently the role of accountants in firms is changing. Increasingly, accountants should have adequate skills not only in terms of financial accounting, but also skills in terms of management accounting that help in the decision-making process and in the performance of firms.The use of management accounting practices, and the respective instruments, has been gaining more and more importance in the business sector, presenting very satisfactory results, contributing greatly to the achievement of a companys competitive advantage over others operating in the same field of activity.There are some studies that suggest a weak influence on the role of management accounting in the decision-making process and in firm or organizational performance, however, they are already somewhat old, namely from the end of the 20th century. However, more recent studies show that many small and medium-sized firms cannot survive in the first years of activity, possibly due to a lack of specialists in decision-making support and they didnt implement Management Accounting (MA).The research objective of this article isto analyse the role of the Portuguese accountant, his skills and how the use of MA can contribute to the firm performance.To meet the research objective, it was decided to apply a quantitative analysis. It was developed a reflective structural equation model (SEM), using a Partial Least Squares method (PLS-SEM), which reveals the influence and impact of the Portuguese accountant and the MA on the firm performance.The results obtained allowed us to conclude that accountants in Portugal recognize the relevance of financial accounting and management accounting for the firm performance, however, they do not give relevance to the complementarity, use and applicability of these two accountings. For accountants in Portugal, management accounting is a complement to the firm performance, not being relevant to financial performance and is less important than financial accounting.