Incorporation of Co²⁺ into the framework of HMOR significantly enhanced the activity for the carbonylation of dimethyl ether to methyl acetate. About 68% of the Co²⁺ cations are located at site A in the 8-membered ring (8-MR) pores, while 32% of the metal cations are incorporated at site E of the 12-MR pores. Although the amount of the Brønsted acid sites in the 8-MR pores that are intrinsically active for DME carbonylation decreased considerably upon Co-doping, the conversion of DME increased remarkably, almost doubled. The promotional role of Co²⁺ in the 8-MR channels was to facilitate the adsorption/activation of both CO and DME molecules. Meanwhile, the Co²⁺ cations located in the 12-MR channels effectively suppressed coke deposition and thus improved the stability of the Co-HMOR catalyst.