Jacoby, an 11th-grader at the Maimonides School in suburban Boston, had been missing since midday on Jan. 6.
The case drew national attention, in part because the youth is the son of Boston Globe columnist Jeff Jacoby.
Some 200 volunteers, including friends and neighbors of the family as well as members of local Jewish groups, searched throughout the Boston area in a coordinated effort on Wednesday. The effort was spearheaded by the Maimonides School.
“Our prayers have been answered,” Jacoby said via Twitter. “We are thrilled to hear from the Brookline Police that our beloved son Caleb has been found and is safe. Words can’t express our gratitude for the extraordinary outpouring of kindness and support that we have received from so many people. All we can think of at this moment is how wonderful it will be to see Caleb again and shower him with love.”