A series of biologically active metal complexes was yielded from the reactions of 2‐(4‐bromophenylamino)acetohydrazide ligand (HL) with Co(II), Ni(II), Cu(II), Cd(II) chlorides, CuBr2, Cu(CH3COO)2, and Cu(ClO4)2 salts. The structure and stereochemistry of the afforded complexes were elucidated by means of elemental analyses, molar conductance, magnetic susceptibility, thermal analyses (TG/DTG), and spectral techniques (mass, IR, UV‐Vis, and 1H NMR). Elemental analyses along with molar conductance data demonstrated that all metal complexes are nonelectrolyte and were formed with 1L:1M, 1L:2M, and 2L:1M stoichiometry. IR spectral data provided an evidence for the neutral bidentate behavior of the hydrazide ligand toward metal ions via carbonyl oxygen and amino nitrogen atoms (ON donor). Magnetic susceptibility along with electronic absorption spectral results authenticated that all complexes have an octahedral geometry except, CuCl2 complex (3), which possessed a square planar one. The hydrazide ligand and some of its synthesized metal complexes were screened in vitro for their antitumor and apoptotic activity. The results showed that CuBr2 complex (4) has promising anticancer activities against breast MCF7, liver HepG2, and colorectal HCT 116 cancerous cells through induction of proapoptotic gene (Bax) and inhibit the antiapoptotic gene (Bcl‐2), thus increase the Bax/Bcl‐2 ratio. Moreover, these newly synthesized compounds were most potent and can be used as a therapeutic chemoprevention against these cancerous cells compared with doxorubicin (DOX), the currently available anticancer drug against solid tumors.