Anti-synthetase syndrome (ASS) is a rare autoimmune disorder of idiopathic inflammatory myopathy spectrum, characterized by the presence of aminoacyl-tRNA synthetase antibodies, most commonly anti-Jo-1. Clinically presents with interstitial lung disease (ILD), myositis, and arthritis, and may be confused with other autoimmune conditions such as polymyositis (PM), dermatomyositis (DM), and Sjögren's syndrome. We present a 41-year-old French-Moroccan woman with progressive dyspnea, dry cough, weight loss, and diffuse myalgia. Extensive autoimmune and laboratory investigations revealed positive anti-histidyl-transfer RNA synthetase (anti-Jo-1), anti-Ro52, and anti-cyclic citrullinated peptide (anti-CCP) antibodies, with elevated creatine phosphokinase (CPK) and lactate dehydrogenase (LDH). Electromyography (EMG) and magnetic resonance imaging (MRI) supported myositis, while chest computed tomography (CT) showed ground-glass opacities and reticulations consistent with fibrosing interstitial lung disease (ILD). She was diagnosed with anti-synthetase syndrome (ASS)-associated ILD. High-dose corticosteroids, cyclophosphamide, and later tacrolimus, alongside supportive care, were provided, which resulted in significant pulmonary function improvement (forced vital capacity [FVC] 56%-92%, diffusing capacity for carbon monoxide [DLCO] 32%-70%) with preserved exercise tolerance. Our case report illustrates the importance of considering ASS in patients with unexplained ILD and myositis. Prompt recognition and combined immunosuppressive therapy can achieve substantial functional recovery and prevent long-term respiratory compromise.