Family surrogates of patients who die in an intensive care unit (ICU) are at risk of cooccurring prolonged grief disorder (PGD), posttraumatic stress disorder (PTSD), and depressive disorder during bereavement, but symptom trajectories are often explored individually. To simultaneously examine and determine co-occurrence of PGD, PTSD, and depressive symptom trajectories. This cohort study was conducted in ICUs of 2 Taiwanese medical centers from January 2018 to March 2020, with follow-up through July 2022. Participants included surrogates responsible for decision-making who provided data 6 to 24 months after the death of their loved one. Data were analyzed from August to December 2022. PGD was assessed with the 11 grief symptom items of the PG-13; PTSD, the Impact of Event Scale-Revised; and depressive symptoms, the depression subscale of the Hospital Anxiety and Depression Scale at 6, 13, 18, and 24 months after the death. Latent growth mixture modeling was conducted to identify distinct trajectories, and joint latent class analysis was used to assess joint patterns of trajectories. A total of 303 participants were included, with most younger than 56 years (207 participants [68.3%]), female (177 participants [58.4%]), and married (228 participants [75.2%]), and their relationship with the patient was mostly spouse (88 participants [29.0%]) or adult child (166 participants [54.8%]). Three trajectories were identified each for PGD, PTSD, and depressive symptoms. A resilience trajectory was predominant across PGD (253 participants [83.5%]), PTSD (250 participants [82.5%]), and depressive (200 participants [66.0%]) symptoms. Second most common was a recovery trajectory identified for PGD (36 participants [11.9%]) and PTSD (41 participants [13.5%]) symptoms, while for depressive symptoms, a moderate trajectory (72 participants [23.8%]) signified persistent moderate distress. A chronic trajectory characterized by persistently high distress was identified for PGD (14 participants [4.6%]) and depressive (31 participants [10.2%]) symptoms, whereas a unique delayed-onset trajectory (12 participants [4.0%]) was identified for PTSD symptoms. Most family surrogates (228 participants [75.2%]) experienced cooccurring PGD, PTSD, and depressive symptom trajectories, but multiple patterns were discordant. Symptom trajectories cooccurred in joint patterns: resilient (247 participants [81.5%]), recovered (43 participants [14.1%]), and distressed (14 participants [4.5%]). These patterns were characterized by high conditional probabilities for the resilience (PGD, 0.999; PTSD, 0.999; depressive, 0.804), recovery (PGD, 0.854; PTSD, 0.890; depressive, 0.588), and chronic (PGD, 0.921; PTSD, 0.789; depressive, 0.980) symptom trajectories. In this cohort study, grief-related psychological symptoms evolved in complex ways during ICU bereavement, as characterized by heterogeneous trajectories. Some ICU bereaved surrogates experienced persistent elevated PGD, PTSD, and depressive symptoms individually or conjointly, underscoring the importance of early screening to identify this population at high risk of comorbid psychological distress trajectories.