The ability to regulate emotion positively impacts one’s mental and physical health. One adaptive emotion regulation strategy is cognitive reappraisal, which involves changing one’s appraisal of an aversive situation to make it feel less negative. Across two different research aims, I examined how cognitive reappraisal relates to health indices via four studies. The first aim was to examine linguistic mechanisms of cognitive reappraisal and investigate how they relate to health indicators. Study 1 examined whether a linguistic signature of cognitive reappraisal relates to positive health outcomes. Specifically, psychological distancing, a form of cognitive reappraisal, involves construal of emotionally-valenced stimuli in an objective manner, or with perceived spatial and temporal distance. Prior work suggests that in appropriate contexts, reappraisal broadly, and distancing specifically, is related to adaptive mental and physical health outcomes. Additionally, recent research suggests that shifting language to be more distant (i.e., linguistic distancing (LD)) can have adaptive emotion regulatory effects. Participants transcribed their thoughts while viewing negative or neutral stimuli in one of three ways: 1) by implementing objective language, 2) by implementing spatially and/or temporally far away language, 3) or by responding naturally. Across psychological distancing groups, LD was associated with lower negative affectivity (lower perceived stress and depression symptoms), better general well-being (better emotional well-being and energy and vitality), and better emotion regulation (ER) (greater reappraisal frequency and fewer difficulties in implementing ER). Participants who used more LD in the objective group had lower negative affectivity, better general well-being, and better ER, and those in the far group had better ER. Study 2 involved developing two Bayesian machine learning algorithms to parse text and identify two key components of language-based psychological distancing: objective language and spatially / temporally distant language. The algorithms produced objective and spatial / temporal distance scores that were positively significantly correlated with human-coded ratings of objective and spatial / temporal distance language, respectively. The second aim was to examine biological substrates of cognitive reappraisal and investigate how they relate to health indicators. Study 3 examined whether cognitive reappraisal impacts the relationship between heart rate variability and telomere length in CD8+CD28– cells. Telomere shortening is related to aging, poor general health, morbidity, and mortality, serving as a prognostic biomarker of health. Heart rate variability (HRV) is the variation in time intervals between heartbeats, and these oscillations in heart rate relate to emotion regulatory processes such as cognitive reappraisal. The association between autonomic nervous system activity and telomere length may change as a function of emotion regulation ability. Study 3 probed these connections by investigating whether cognitive reappraisal impacts the relationship between telomere length in leukocytes (among CD8+CD28– cells) and HRV. Participants completed measures of cognitive reappraisal frequency, HRV, and underwent blood draws to measure telomere length in CD8+CD28– cells. Cognitive reappraisal moderated the relationship between telomere length and HRV. Study 4 investigated whether neural correlates of cognitive reappraisal impact the relationship between perceived stress during exposure to negative stimuli and attention deficits. Perceived stress has been shown to have negative consequences for physical and mental health, including cognitive deficits and difficulties controlling attention. Reappraisal can be implemented explicitly or implicitly (i.e., with or without conscious awareness). I found, as expected, that inattention problems are associated with increased perceived stress, but also found that one’s spontaneous propensity to engage in cognitive reappraisal—as indexed by correspondence with a reliable thresholded whole-brain pattern of reappraisal implementation—moderated the relationship between inattention and perceived stress. Overall, the studies shed light into the mechanisms underlying cognitive reappraisal as well as the impact it has on biomarkers of health.