Background: Autologous fat grafting (AFG) is commonly used as part of aesthetic and reconstruction procedures, but expanding and enhancing the recipient site capacity remains a major challenge. Objectives: The aim of this study was to describe and assess an innovative intraoperative carbon dioxide (CO2) pneumodissection (CPD) recipient site preconditioning procedure intended to improve recipient site capacity and AFG outcomes. Methods: From June 2019 to August 2021, 53 patients after mastectomy or lumpectomy (76 breasts) underwent 96 AFG procedures as a separate stage immediately following tissue preconditioning with CPD. Results: There were no systemic or major local complications. The mean number of AFG procedures required to complete the reconstruction was 1.3 per breast. The vast majority of patients achieved a final satisfactory aesthetic outcome with either 1 or 2 procedures (77.6% and 18.4%, respectively). The volume of fat graft delivered into the recipient site per session following CPD was higher than previous literature reports for all study groups. Furthermore, the CPD procedure was associated with a reduced need for subsequent AFG to complete the reconstruction. The positive effect of CPD, in terms of AFG volume delivered, was even more prominent among scarred irradiated breasts. Despite the large fat graft volumes delivered in our study, only 5.3% of breasts experienced fat necrosis following the procedure. Conclusions: CPD constitutes a safe, innovative, intraoperative method to expand and enhance recipient site capacity and fat grafting outcome. CPD allows cavernous expansion alongside preservation of the microcirculation. CPD works for both healthy and compromised tissues, in either reconstructive or aesthetic procedures.