Introduction: Although several treatments for faecal incontinence are available, gas incontinence (GI) and soiling are difficult to manage. The aim of this study is to evaluate Gatekeeper™ for this subtype of faecal incontinence. Methods: Prospective single-centre case series. Patients with mainly soiling and/or GI were treated with polyacrylonitrile prostheses. An evaluation was performed with a 3-week continence diary. St. Mark’s score and a Visual Analogue Scale (VAS) were used to study the patient’s continence perception and surgical satisfaction, at baseline and 1, 3, 6, 12, and 24 months postoperatively. 3D-Endoanal Ultrasound and Anorectal Manometry were performed at baseline and postoperatively. Results: A total of 13 patients were enrolled (11 women), aged (median (IQR)) 62 (13) years, and all implants were uneventful. A significant reduction in soiling and GI episodes was documented at 1 year, 7 (18) baseline days of soiling/3 weeks vs. 2 (4) (p = 0.002); 13 (13) baseline episodes of GI/3 weeks vs. 4 (10) (p = 0.01). This improvement was correlated with a significant increase in VAS (0–10), 3 (2, 5) baseline vs. 7 (1, 5) (p = 0.03), and maintained throughout the follow-up. There was complete remission or significant improvement defined as >70% reduction in gas and soiling days in 6 patients at 2 years follow-up. Soiling episodes were reduced ≥70% in 8/11 patients (72.7%). Nine (70%) patients would repeat the treatment. Conclusions: Gatekeeper™ is a safe, minimally invasive treatment for soiling and GI. A significant reduction in soiling and GI was observed in our series, with a better response to soiling. Most of the patients would repeat the treatment. Other studies are needed to confirm these findings in this subgroup of FI patients.