The left-back revealed that he turned down offers from elsewhere before putting pen to paper on a four-year contract with the Portuguese giants
The Argentina international only arrived in the Russian capital in 2011 but the left-back has now sealed a switch to the Jose Alvalade, penning a four-year contract with the Primeira Liga outfit.
"I felt great excitement in these past few days before arriving at Sporting, a truly great club," Rojo told his new side's official website.
"It's true that I had other offers, but I was captivated by how much interest Sporting showed in signing me.
"I felt it was the best option for my career and I am naturally very happy to finally be able to wear this jersey."
The 22-year-old Rojo, who has been capped nine times by his country, is a product of the Estudiantes youth academy.