Using a conjunction of Cluster in the mid‐altitude dayside magnetosphere and Swarm in the low‐altitude ionosphere, we show, by employing multi‐spacecraft analysis, that matched, strong magnetic perturbations and the corresponding mesoscale field‐aligned current (FAC) structures are measured in the high latitude polar cusp region during the 7 October 2015 storm. Two pairs of opposite (positive/negative) FACs are observed by both Cluster and Swarm, which may relate to pulsed magnetic reconnection at the dayside magnetopause. Furthermore, the current intensity of these matched FACs decreases from high to low latitude, consistent with the time elapsed since reconnection. Corresponding geomagnetic disturbances are also observed by ground stations. Our observations provide direct evidence for the coupling of mesoscale FACs between the magnetosphere, ionosphere and ground in the polar cusp region, where the signatures are driven in this case by conditions suitable for inducing reconnection. Plain Language Summary Field‐aligned currents (FACs) are the key medium for the interaction between the distant space magnetosphere (a region filled with Earth's magnetic field) and the near‐Earth space ionosphere. Magnetic reconnection is the most important process to transfer solar wind energy from dayside magnetosphere to nightside, which is accompanied by the generation of FACs extending from the high latitude region of the ionosphere to the magnetosphere. For such structures, extending across different space regions, joint observations by multiple spacecraft are necessary. Using simultaneous measurements of Cluster in the magnetosphere, Swarm in the ionosphere and geomagnetic stations on the ground, coordinated mesoscale FAC structures could show matched signatures in the magnetosphere and the ionosphere and the corresponding geomagnetic disturbances on the ground. Our observations provide direct evidence for the magnetosphere‐ionosphere‐ground coupling during the pulsed magnetic reconnection process. Key Points Multi‐spacecraft Cluster and Swarm reveal matched magnetic perturbation and corresponding mesoscale field‐aligned currents (FACs) at different altitudes in the cusp region Multiple pairs of opposite FACs associated with pulsed magnetic reconnection are dominant currents system at the dayside during storm time Direct evidence for detailed dayside mesoscale FACs coupling between magnetosphere, ionosphere and ground is provided