Modern agricultural production faces significant challenges including soil degradation, climate change and rising costs within production systems. Biochar, a carbon-rich material obtained by pyrolysis of organic waste biomass, is emerging as one of a series of steps towards sustainable crop production. This review paper analyses the basic physicochemical properties of biochar and its role as a soil conditioner, with an emphasis on its ability to increase water holding capacity, cation exchange capacity (CEC) and to regulate soil reaction, especially on degraded soils. Beyond agronomic benefits, biochar serves as a “Negative Emission Technology” by sequestering carbon for centuries and mitigating greenhouse gas emissions. In the Republic of Croatia, research focuses on acid soils and valorising viticultural residues. Innovative applications, such as foliar biochar sprays for grapevines and the use of sewage-sludge-derived biochar for heavy metal adsorption, demonstrate its versatility. While biochar acts more as a long-term soil amendment than an immediate corrective agent, its integration into Croatian agroecosystems follows a science-based pathway; however, the adoption of biochar-based products is still not at a high level.