Mechanoluminescence (ML) and long-afterglow (LAG) luminescence are usually studied independently and applied in different fields. SrAl2O4:Eu(II)/Dy(III) (SAOED) is a well-known long-afterglow and elastico-mechanoluminescent material that emits bright green visible light through absorption of photon energy, followed by naturally thermal release or excitation by force. The ML intensity is directly proportional to the magnitude of the applied dynamic force in the elastic range, making it uniquely applicable in a wide field of active visualization of stress/strain sensing. As a LAG material, SAOED is also a commercial photoluminescence (PL) phosphor owing to its high initial brightness and ultralong luminescence duration. Considering the ML and LAG properties and making better applications, the influence of dopants on both characteristics should be studied. In this study, we investigated the concentration effect of Eu (II) and Dy (III) co-doping on the PL, ML, and LAG properties of SAO. A maximum twofold ML brightness enhancement was achieved, and a suitable stress-induced afterglow and stress-free afterglow features were observed through Eu(II) and Dy(III) co-doping. Taking advantage of these properties, we demonstrate the application of Dy- and Eu-co-doped strontium aluminate in environmental–mechanical energy conversion. Owing to its mechanically excited luminescence properties, it can reduce electricity consumption and can also serve as an environmental motion warning in traffic signing, sports scene, and other related fields. The results enriched the application scenarios of SAOED composites as a multiluminescent smart material.