Liquid column dampers are adjusted based on the characteristics of the host structure and the type of external forces. It is assumed in most studies that the structure is rigidly connected to the ground, and the characteristics of the structure are invariant during external excitations. The performance of passive dampers may lose, or structural displacements may be increased by changing these conditions. This study presented a new method to find the optimal control forces for structures equipped with smart tuned liquid column gas damper (TLCGDs), considering variable characteristics of the structure and the soil–structure interaction. The proposed method calculates the gas pressure inside the columns by regularly adjusting and updating the frequency and damping of the TLCGD. The unknown or changed soil–structure characteristics are estimated by a system identification method, and damper parameters are determined through an optimization algorithm. The method was tested on 3- 9- and 10-story shear buildings under harmonic and earthquake excitation. According to the results, the smart damper more effectively reduced the structural displacement.