Timber-concrete hybrid buildings are an innovative solution to increase the amount of timber materials used in modern buildings. This study presents a dynamic evaluation of a nine-story timber-concrete hybrid residential building during construction. The building consists of a seven-story structure in cross-laminated timber (CLT) on top of two stories in concrete. Ambient vibration tests were conducted seven times during the 13-month construction period, including tests with only the structural elements in place and tests of the finished building with the façade, non-structural walls, and other internal finishing. The results show a clear decrease in the natural frequencies of the building as the building gets higher and more elements are installed. However, a slight increase in the natural frequency was observed following the installation of the non-structural walls in the final construction stage. A corresponding finite element analysis is presented for each test, providing additional insights into the parameters typically used in the structural design process. The study demonstrates the importance of properly selecting reduction factors for CLT elements in a dynamic finite element analysis. It also shows the importance of considering non-structural walls, both regarding weight and stiffness, even in buildings where the number of non-structural walls is relatively small compared to structural walls.