Background The COVID-19 pandemic has caused unprecedented challenges in healthcare, particularly for patients with severe cases requiring invasive mechanical ventilation (IMV). Such patients often develop post-intensive care syndrome (PICS), characterized by physical, cognitive, and emotional impairments, severely affecting their health-related quality of life (HRQoL), functional capacity, and reintegration into society. Objective This study aimed to evaluate the evolution of HRQoL, functional capacity, nutritional status, and return to work one year after intensive care unit (ICU) discharge in adults with severe COVID-19 who required IMV for over 72 hours. Methods A prospective, longitudinal cohort study was conducted between June and December 2020, including 51 patients discharged from the ICU and subsequently followed up for one year. HRQoL was assessed using the EuroQol five-dimension, three-level (EQ-5D-3L) questionnaire and visual analog scale (EQ-VAS). Functional capacity was measured via the Katz Index (KI) and Timed Up and Go (TUG) test. Nutritional status was evaluated through anthropometric measures, including body mass index (BMI) and muscle circumference. Employment reintegration was tracked among pre-hospitalisation workers. Results A total of 51 subjects were enrolled in the follow-up program. Only 26 patients (50.9%) attended all scheduled visits. The mean age was 53.4 years, and 34 (68%) were men. A significant improvement was observed in EQ-5D-3L index scores, functional capacity, and muscle strength. Anthropometric indicators increased significantly between one month and one year after hospital discharge. Among those who were previously employed, 11 patients (69.6%) returned to work by the end of the follow-up period, and the overall 1-year mortality was 6 patients (12.2%). Conclusion Patients with severe COVID-19 requiring IMV experienced significant impairments in HRQoL, functional independence, and nutritional status at hospital discharge. Over the year-long follow-up, notable improvements were observed in these domains, particularly in muscle strength, anthropometric indicators, and functional outcomes. However, pain and discomfort remained unchanged, reflecting persistent physical sequelae. With 69.6% of patients returning to work, functional and social recovery was evident, despite lingering limitations. These findings highlight the need for interdisciplinary follow-up programs to support the comprehensive recovery of this population.