The excited states in ⁷³Br nucleus have been investigated through the fusion evaporation reaction ⁵⁰Cr(²⁸Si, αp) ⁷³Br at a beam energy of 90 MeV using the Indian National Gamma Array. The γ-γ coincidence technique has been used to add eight new γ-ray transitions in the level scheme. The mixing ratio of ΔI = 0 (mixed with E2 and M1) transitions have been determined using angular distribution and R_DCO-polarization measurement. The half-life of the 9/2⁺ isomeric state has been measured to be τ_1/2 = 52(2) ns from the variation in the intensity of delayed γ-ray transition as a function of coincidence time window. The two state mixing model calculations were performed to obtain the mixing amplitude, and mixing interaction of two different configurations of ⁷³Br. The calculated mixing amplitudes along with the deformations of two different configurations provide the monopole transition strength ρ2 (E0) for Se, Br, and Kr isotopes in a semiempirical approach. These results support a prolate-oblate shape coexistence in the odd-A ⁷³Br nucleus. The observed structural properties have been discussed in terms of projected shell model calculations.