["Journal of Traumatic Stress, EarlyView. ", "\nAbstract\nThe processing of positive memories technique (PPMT) is a promising new treatment for posttraumatic stress disorder (PTSD) involving the detailed narration and processing of specific positive autobiographical memories. This study used an interrupted time series design with daily diary reports to assess changes in daily‐level affect, cognitions, and PTSD symptoms pre‐ to post‐PPMT. A convenience sample of trauma‐exposed U.S.‐based adults (n = 70) recruited through social media and flyers received the 4‐week PPMT intervention and completed 21 daily surveys pre‐ and post‐PPMT (42 total surveys) assessing daily positive event pleasantness, negative event unpleasantness, PTSD symptoms, posttraumatic cognition levels, and positive and negative affect levels. Mixed‐effects models found post‐PPMT reductions in daily negative event unpleasantness ratings, β = −.25, p < .001; PTSD symptoms, β = −.24, p < .001; posttraumatic cognition levels, β = −.32, p < .001; and negative affect levels, β = −.32, p < .001, alongside increases in daily positive affect levels, β = .12, p = .021, compared with the preintervention phase. The association between daily negative event unpleasantness and daily negative affect levels (negative affect reactivity) was weaker postintervention compared with preintervention. There was no significant change post‐PPMT in positive event pleasantness ratings, β = −.03, p = .619, or the association between daily positive event pleasantness and daily positive affect levels (positive affect reactivity), β = .00, p = .931. These findings provide support for the beneficial therapeutic effects of PPMT at the daily level for trauma‐exposed populations. Further studies should test these patterns with clinical samples.\n"]