In previous studies, we have reported that double perovskite La₂NiMnO₆ presents non-negligible potential for room temperature magnetocaloric tasks. With the aim of improving even further the cooling performances and the working temperature range of double perovskites, we report the magnetic and magnetocaloric properties of La₂MnFeO₆ and ALaMnFeO₆ (A = Sr, Ba, and Ca) compounds. X-ray diffraction and Rietveld refinement show that La₂MnFeO₆ (LMFO) and CaLaMnFeO₆ (CLMFO) samples crystallize in an orthorhombic structure with the P n m a space group. However, a rhombohedral structure with the R 3 ? C space group is obtained for BaLaMnFeO₆ (BLMFO) and SrLaMnFeO₆ (SLMFO) samples. Substituting La by Ba or Sr in LMFO leads to a clear increase of the Curie temperature (T_c) compared to LMFO from 150 K for BLMFO up to 350 K for SLMFO. Moreover, CLMFO shows the smallest T_c down to 70 K. Ferromagnetic-like behavior is observed for SLMFO and BLMFO, while CLMFO's magnetism resembles that of LMFO. A clear connection between the structural parameters and the magnetic properties of these doped LMFO samples is unveiled as the highest T_c and the largest magnetization are observed for SLMFO which also shows bond angles closest to 180° and the smallest bond lengths, thus optimizing the superexchange interaction. The partial substitution of Sr for La leads, in fact, to a significant magnetocaloric effect over a wide operating temperature range extending beyond 300 K. For some optimal growth conditions, its entropy change varies slowly over an unusually large temperature range, which is of clear interest from a practical point of view.