Soft cheeses were manufactured from bovine milk with the addition of 0–12% sesame protein isolate (SPI) were utilised to investigate rheology, texture and microstructure at different stages of cheese making. SPI addition reduced the speed of milk fermentation, kappa-casein proteolysis of rennet and elongated the time of cheese curd formation. Renneted milk storage modulus G′60min was decreased and coagulation time increased with increasing SPI content. Low SPI supplements (4% and 8%) enhanced the hardness, cohesiveness, adhesiveness and gumminess of the soft cheese, while high SPI addition (12%) deteriorated the texture. In the cheese curd gel matrix, SPI distributed as specific SPI-gel clusters on the surface of curd fractures, stacked or fused with ball-shaped casein micelles and wrapped up to casein gel strands. In summary, SPI actively interacted with casein colloid throughout the cheese making process.