Schweinsteiger, who was sidelined for a couple of days before returning to training on Monday, has yet to peak in this tournament after being hampered by the injury picked up earlier in the year and has struggled with his movement and speed.
"Obviously he can do things better than against Greece (in the 4-2 quarter-final win) but we need Bastian," Loew told reporters on Tuesday.
"He is an emotional leader for us. He has matured unbelievably in the last three years or so. I think it is important for our team when Bastian Schweinsteiger is there."
The holding midfielder, who started all three group games and the quarter-final, has said he would not object to sitting on the bench after criticising his own performance so far.
Germany have won their last 15 competitive games and are chasing their first trophy since 1996.
"Bastian has the stamina needed. Maybe he was lacking a bit of mobility against Greece but it is extremely important for us when Bastian is on the pitch."
"He is as confident as we need him to be," said Loew.