<i>Background:</i> Due to the long duration of treatment and the emergence of multidrug-resistant strains, new antitubercular agents are urgently needed. I2906, as a novel lead, was screened and tested for efficacy in vitro and in vivo. <i>Methods:</i>To determine the efficacy of I2906,the minimum inhibitory concentrations against <i>Mycobacterium tuberculosis</i> and cytotoxicity were tested, and its in vivo activities were assessed by administering it to mice infected with <i>M. tuberculosis</i> H37Rv or multidrug-resistant strain. <i>Results:</i>Under in vitro conditions, I2906 showed excellent antimycobacterial activities and low cytotoxicity. In a murine model infected with <i>M. tuberculosis</i> H37Rv, the reductions on bacterial loads of both lungs and spleen were statistically significant (p < 0.05) between I2906-treated mice and untreated controls after 4 weeks. Further, the colony-forming unit counts in the lungs were dramatically lower (p < 0.05) than that of isoniazid-treated mice by the addition of I2906 after 8 weeks. Moreover, survival rate was increased by I2906 treatment. For multidrug-resistant strain infection, bacterial counts were reduced significantly in the lungs and spleen due to I2906 treatment in comparison with data from untreated controls (p < 0.05). <i>Conclusions:</i> I2906 displayed potential antimicrobial activities against <i>M. tuberculosis</i> H37Rv and drug-resistant strains in vitro and in vivo, and could improve efficacy of isoniazid in vivo.