“Metacontrol” refers to the ability to achieve an adaptive balance between more persistent and more flexible cognitive-control styles. Recent evidence from tasks focusing on the regulation of response conflict and of switching between tasks suggests a consistent relationship between aperiodic EEG activity and task conditions that are likely to elicit a more persistent versus more flexible control style. Here we investigated whether this relationship between metacontrol and aperiodic activity can also be demonstrated for working memory (WM). We analyzed EEG and behavioral outcomes from two independent samples performing the reference-back task, providing an internal replication of the obtained findings. In both studies we found significant increases in the aperiodic exponent when new information needs to be taken in, showing that the updating of WM is likely associated with a metacontrol bias towards persistence. This observation demonstrates a role of aperiodic activity and/or mechanisms associated with changes in this activity in a memory task, which suggests that the relationship between metacontrol and aperiodic activity extends beyond tasks with particular response-selection demands. Further, metacontrol adjustments do not seem to create particular states that differ in aperiodic activity, but rather to bias the way selections are carried out, presumably by reducing aperiodic activity whenever the selection is particularly challenging. We advocate that the aperiodic activity observed in EEG signals represents a valid indicator of the neural dynamics underlying metacontrol, portraying the brain's inherent potential to self-reorganize and alter neural functions to mutable environmental conditions.