Aims Hot springs have always drawn attention due to their unique chemical richness and the presence of different microbial communities. The use of hot spring bacteria in concrete technology is our primary focus; isolation of an alkaliphilic bacterium from the Bakreshwar hot springs having longer survival and better efficacy towards cementitious environment was the basis of our study's design. Methods and Results A novel facultative anaerobic and highly alkaliphilic bacterial strain (BKH4; GenBank accession no. KX622782) belonging to the family ‘Bacillaceae’ and homologous (99%) with Lysinibacillus fusiformis was isolated from Bakreshwar hot springs. The isolated coccoid‐type Gram‐positive bacterium grows well in a defined semi‐synthetic medium (pH 12·0 and 65°C). This bacterium survives for more than a month and shows better efficacy in enhancing compressive strengths (>50%), ultrasonic pulse velocity (>25%) and durability of the cementitious mortar when incorporated at a concentration of 104 cells per ml of water used. Conclusion The novel bacterium BKH4 is more effective for the enhancement of the bioconcrete properties. Significance and Impact of the Study BKH4 bacterium will add a new dimension to future concrete technology for its usefulness in strength enhancement and durability due to its alkaliphilic nature and longer survival within a cementitious environment.