Analyzing the microstructural behavior of materials operating under fluctuating temperature conditions has become essential, as these fluctuations significantly impact material properties at both micro and molecular levels. Studying stainless steel is essential since it is a material that is used extensively in a variety of temperature ranges. Investigating how heat treatment affects the mechanical properties, microstructural growth, and deformation behavior of grade 304 stainless steel is the goal of this study. Due to its widespread usage and good performance in temperature-variable situations, stainless steel grade 304 is employed in this study for heat treatment and microstructural examination at room temperature and higher temperatures. The full annealing was conducted at room temperature, as well as at 1010 and 1120 °C. The annealing process led to small, redistributed grains in the deformed material, which improved its properties compared to untreated SS304. Post-annealing, the material exhibited an increase in fine, equiaxed grains and a reduction in large, elongated grains. The annealed samples at 1010 and 1120 °C demonstrated microstructural changes along cellular walls, where a limited number of dislocations unraveled. This suggests that annealing may prompt dislocation along cellular walls to move to more energetically stable regions, fostering the formation of sub-grain boundaries and enhancing the mechanical characteristics of SS304.