This study proposes a passive structural vibration control strategy based on the use of a sliding variant of the well-known Tuned Liquid Column Damper device (referred to as STLCD) and examines both theoretical and experimental perspectives. The STLCD configuration consists of a U-tube container filled with liquid that can slide along a linear guide rail and is connected to the structure by a spring-dashpot system. This setup, unlike conventional fixed TLCDs, offers the flexibility of tuning for short-period systems since the spring can be used for tuning and the dashpot for added damping. However, similar to TLCDs, the STLCD also shows slightly nonlinear behavior, hence, an equivalent linear mechanical model is employed to streamline the analyses necessary for the optimal design of the device. In particular, the selection process of the optimal design parameters of the STLCD is discussed, assuming a Gaussian white noise process as base excitation, with the aim of minimizing the total acceleration variance of the structural system. To validate the introduced mathematical formulation, experimental tests are conducted at the Laboratory of Experimental Dynamics at the University of Palermo, Italy, examining both time and frequency domains. Finally, the control performance of a scaled model of an STLCD-controlled structure is evaluated against its uncontrolled counterpart and commonly used devices such as the TLCD and the Tuned Mass Damper (TMD), under harmonic excitations, providing a comparative analysis.