This work reports on the luminescence properties of cerium and samarium co-doped in yttrium aluminum garnet, (Ce, Sm) co-doped YAG, ceramic. Single and co-doped YAG nanocrystals have been prepared at different contents of Ce ions. The x-ray diffraction (XRD) technique confirms the formation of the crystallites and the phase purity. The ceramic has been fabricated by sintering process using Spark Plasma Sintering (SPS) technique. It is found that the photoluminescence (PL) spectral features of ceramic sample are strongly dependent on the excitation wavelength. Broad emission band from Ce3+, in blue-green region, is superimposed with the emission lines from Sm3+, in reddish orange region, thanks to significant spectral overlapping of their excitation lines. This led to manipulate the relative PL spectral contribution from each ion based on the excitation wavelength. As a consequence, the emitted color parameters can be controlled from yellow/green zone to white color zone, as demonstrated from the chromaticity diagram. In addition, cathodoluminescence (CL) has been performed and evidenced a strong superimposed CL signal from both ions. Moreover, the time-resolved photoluminescence (TRPL) result indicates the influence of such spectral overlapping on the luminescence decay kinetics. This study attempts to highlight on the optical properties of such coupling between Sm and Ce that can be exploited in several lighting based applications.