A hybrid sulfated galactan (κ-/β-carrageenan) was extracted from wild and cultivated Betaphycus gelatinus using cold (25 °C) and hot (95 … 110 °C) alkaline extractions, followed by alkali treatment to convert residual precursors into primary carrageenan forms. Structural analysis of native and alkali-treated galactans from both sources using HP-SEC, HPICE, HPAEC, FTIR, FT-Raman, and NMR revealed no significant differences in molecular weight, monosaccharide composition, sulfate content, or structural characteristics. NMR analyses confirmed that alkali treatment converted γ-carrageenan into β-carrageenan through desulfation. Enzymatic depolymerization with κ-carrageenase further investigated the distribution of κ- and β-carrabiose moieties. It was confirmed that the enzyme-resistant fraction was enriched in β-carrageenans, whereas the enzyme-sensitive fraction contained abundant oligo κ- or κ/β-carrageenans, indicating a block-wise distribution of κ- and β-carrageenan diads in the polymer. Dynamic rheometry was used to assess the effects of alkali treatment and counter ions (K+, Ca2+, Ba2+) on the thermo-rheological properties of the hybrid galactan gel. This study provides the first evidence of the strong gel-forming capability of Betaphycus polysaccharides, especially in cultivated samples with K+ ions. It also highlights the impact of block-wise versus random distribution of κ- and β-moieties on gel formation. Alkali-modified κ/β-carrageenans from B. gelatinus emerge as a sustainable, versatile hydrocolloid with promising applications in the food industry, due to their excellent solubility, controlled gelation, and ability to form transparent, thermo-reversible gels under low salt conditions.