There are different ways to reduce the CO2 amounts emitted from concrete production, e.g., carbon capture during the cement production, application of low-clinker binders, or changing the structural design strategies to decrease the total consumption of overall materials. Another vital approach is to foster the application of locally available resources, which does not require a significant amount of energy for the production and transport, and which could be used as cementitious materials without compromising the properties of the concrete. Biochar, produced by pyrolysis, is a potentially promising material for improving the sustainability of cementitious materials as it can sequester CO2 and can be made widely available. However, its use in concrete is limited due to negative effects on concrete properties at dosages that can have a significant effect on the carbon footprint. These effects depend on the source of raw biomass and pyrolysis conditions. Biochar’s high porosity leads to the absorption of mixing water, altering the water to cement ratio and rheology. Superplasticizers can help adjust this, but at the cost of longer setting times. High levels of biochar also reduce the mechanical properties of cement-based materials. Currently, the maximum replacement of cement with biochar without compromising mechanical properties is 5–10%. However, to increase the CO2 reduction potential, the content of biochar in cement-based materials must be increased. The current paper suggests possible strategies to promote the use of biochar in cementitious materials to increase its CO2 reduction potential and pave the way to net-zero concrete technologies.