Ischemia and reperfusion (IR) injuries may produce deleterious effects on hepatic tissue after liver surgery and transplantation. The consequences of IR are more evident in pathological steatotic livers. Spirulina (Arthrospira platensis) is known for its potential to modulate inflammatory responses and enhance antioxidant defenses. The current investigation assessed whether spirulina pretreatment mitigates hepatic IR injury exacerbated by steatosis in rats. Thirty male Wistar rats were divided into five groups: sham, IR, HFD, HFD + IR, and SP1000 (HFD + IR + spirulina 1000 mg/kg/day; oral gavage). Liver injury, oxidative stress, inflammatory signaling, and inflammasome/pyroptosis-related markers were assessed using serum transaminases, hematoxylin–eosin staining, immunofluorescence, and qRT-PCR. High-fat diet-fed rats developed steatosis, which significantly worsened IR-induced liver damage, as shown by the respective steatosis histological score, the elevated alanine aminotransferase (ALT) and aspartate aminotransferase (AST), and higher expression of inflammatory markers, including Toll-like receptor (TLR4), nuclear factor kappa B (NF-κB), tumor necrosis factor alpha (TNF-α), and interleukin-1 beta (IL-1β) and inflammasome/pyroptosis-related transcripts, namely NOD-like receptor family pyrin domain-containing 3 (NLRP3), interleukin-18 (IL18), and gasdermin D (GSDMD). Oxidative stress was exacerbated, as reflected by higher levels of malondialdehyde (MDA) and reduced antioxidant defenses (superoxide dismutase (SOD) activity, reduced glutathione (GSH) content, glutathione peroxidase (GPx) expression, and heme oxygenase-1 (HO-1) expression). Furthermore, HFD + IR upregulated sterol regulatory element-binding protein-1c (SREBP-1c) expression and downregulated AMP-activated protein kinase (AMPK) expression. Spirulina supplementation significantly attenuated liver injury and transaminase release, reduced MDA, restored antioxidant parameters, downregulated inflammatory and inflammasome-related gene expression, and shifted both SREBP-1c and AMPK expressions toward control levels.