Considering their potential to contribute to sustainable development, the promotion of circular construction strategies, including structure reuse, is increasing. Unlike traditional building design practices, design for reuse includes the development of structures which could be easily disassembled, transported and reassembled at the end of each building life cycle. Another reuse approach is reflected in the implementation of the material reclaimed from existing structures in the new buildings. This paper contributes to the development of reusable building practices by introducing an innovative solution of the beam-to-column connection designed for application in reusable moment-resisting steel frames. The developed joint is designed as fully demountable, realising the connection through preloaded bolts and avoiding the implementation of welds, enabling the reuse of each structural member. Moreover, the joint is designed to enable the reuse of steel reclaimed from existing structures, providing an additional connecting link to enable an extension in the service length of existing steel members and their adjustment to the designed span of the new structure. Experimental work has been conducted to test the component performances, assess failure mode and determine joint moment resistance, rotation capacity and stiffness. The influence of the connecting link steel grades on the rotational deformation of the connection and the shear deformation of the column web panel was thoroughly examined. The standard material tests on joint components and the imperfection measurements on the reused steel members were also conducted. The commercial software ABAQUS was used to create FE models aiming to simulate the mechanical features of the test joint configurations and predict aspects of their structural behaviour in a wide range of different influencing parameters.