The Brazil international has at last completed his move to the Morumbi outfit after signing a five-year deal upon the completion of his medical.
The Morumbi side was eager to bring in a replacement for Lucas Moura, who will leave the club for Paris Saint-Germain in the January transfer window, and has now found its man in Ganso.
The Tricolor Paulista have acquired 45 percent of the attacking midfielder's economical rights, with the remaining 55 percent remaining with investment company DIS.
"I am very happy with this move. This is a dream come true. Other clubs also showed an interest in signing me, but Sao Paulo was my first choice right away. I can't wait to repay them for all they've done to sign me," Ganso said.
Ganso had set his sights on a move away from Santos after the club refused to meet his wage demands, following his request for a significant pay rise.
Flamengo and Gremio had also shown an interest in luring the player away from Santos, but the 22-year-old will now continue his career at Sao Paulo instead.