The excited states of the $^{199}\mathrm{Tl}$ nucleus have been studied by using the light ion induced fusion evaporation reaction $^{197}\mathrm{Au}(\ensuremath{\alpha},2n)^{199}\mathrm{Tl}$ at 30 MeV of beam energy by $\ensuremath{\gamma}$-ray spectroscopic methods. VECC Array for NUclear Spectroscopy (VENUS) has been used to detect the prompt $\ensuremath{\gamma}$ rays. Level scheme of $^{199}\mathrm{Tl}$ has been significantly improved and extended with the placement of 53 new transitions. The yrast $\ensuremath{\pi}{h}_{9/2}$ band has been extended in this nucleus beyond the band crossing. Several new near- and non-yrast band structures have also been identified. It has been observed that in case of the three-quasiparticle structures, a different configuration involving negative parity neutron orbitals becomes yrast for heavier Tl isotopes with $N\ensuremath{\ge}118$ in contrast to the involvement of the neutron ${i}_{13/2}$ orbital for lighter Tl isotopes. It was possible to identify both the yrast and the non-yrast states corresponding to these configurations in the present work. The observed band structures have been interpreted in light of the systematics of the neighboring odd mass Thallium nuclei. Total Routhian surface calculations have been performed to study the deformation and shape changes as a function of rotational frequency in this nucleus.