We have assessed the effect of endogenous compounds/modulators on the cardiac ion channel Kv7.1/KCNE1 and identified modulators belonging to the major classes of endocannabinoids, free fatty acids, steroid hormones, sterols, and reactive oxygen species. We find support of specific endogenous modulators within these classes as putative resilience factors (through channel activation), whereas others are putative trigger factor (through channel inhibition). For endocannabinoids, free fatty acids, and steroid hormones, we have provided mechanistic insights into where on the ion channel protein these modulators act, how they induce their effects, and what structural elements of the modulators a required to induce effects. We have identified mutation-specific responses of each class of modulator, with some mutations being clearly responsive whereas other mutations are left without modulator effects. Moreover, we find that the effects are translational between different experimental models addressing different aspects of cardiac function. Altogether, our work supports the concept of endogenous compounds implicated in cardiac arrhythmia acting as ion channel modulators and that their effect depends on the genetic background. For some endogenous modulators, we have utilized the gained mechanistic insights to develop synthetic Kv7.1/KCNE1 channel modulators, which are being explored as pharmacological agents.