Research has indicated that patients’ in-session experience of previously avoided affects may be important for effective psychotherapy. The aim of this study was to investigate patients’ in-session levels of affect experiencing in relation to their corresponding levels of insight, motivation, and inhibitory affects in initial Experiential Dynamic Therapy (EDT) sessions. Four hundred sixty-six 10-min video segments from 31 initial sessions were rated using the Achievement of Therapeutic Objectives Scale. A series of multilevel growth models, controlling for between-therapist variability, were estimated to predict patients’ adaptive affect experiencing (Activating Affects) across session segments. In line with our expectations, higher within-person levels of Insight and Motivation related to higher levels of Activating Affects per segment. Contrary to expectations, however, lower levels of Inhibition were not associated with higher levels of Activating Affects. Further, using a time-lagged model, we did not find that the levels of Insight, Motivation, or Inhibition during one session segment predicted Activating Affects in the next, possibly indicating that 10-min segments may be suboptimal for testing temporal relationships in affective processes. Our results suggest that, to intensify patients’ immediate affect experiencing in initial EDT sessions, therapists should focus on increasing insight into defensive patterns and, in particular, motivation to give them up. Future research should examine the impact of specific inhibitory affects more closely, as well as between-therapist variability in patients’ in-session adaptive affect experiencing.