"Not surprised the NRA reeled President Trump back in," Schumer said in a statement. "Just amazed at how fast it happened."
Schumer's comment came after another statement earlier Thursday, in which he accused Trump of having caved to the NRA's demands on gun reform in the past.
"I hope this time will be different," Schumer said in the earlier statement.
Trump signaled a shift on gun control reform this week after facing pressure in the wake of a deadly shooting at a South Florida high school.
He suggested in a tweet Thursday that his administration would push for stricter background checks for gun purchases, and would seek to raise the age to buy guns.
But he also voiced support for a plan to implement concealed carry for highly trained teachers, and get rid of gun-free zones around schools.
Schumer's second statement on Thursday did not follow any further comments from Trump.
In another tweet on Thursday, Trump defended the NRA, which has faced intense scrutiny in recent days, calling the organization's leaders are "Great People and Great American Patriots."