CHICAGO — A couple of weeks ago, Barack Obama headed to the Hyde Park Hair Salon for a trim. He greeted the staff and other customers and plopped down in the same chair in front of the same barber who has cut his hair for the last 14 years.

But when he wanted a trim this week, the Secret Service took one look at the shop’s large plate-glass windows and the gawking tourists eager for a glimpse of the president-elect and the plan quickly changed. If Mr. Obama could no longer come to the barber, the barber would come to him and cut his hair at a friend’s apartment.

Life for the newly chosen president and his family has changed forever. Even the constraints and security of the campaign trail do not compare to the bubble that has enveloped him in the 10 days since his election. Renegade, as the Secret Service calls him, now lives within the strict limits that come with the most powerful office on the planet.

He has chosen to spend this interval before his Jan. 20 inauguration at his home in Hyde Park, which has in some ways been transformed into a secure fortress for his protection. After two years of daily speeches and rallies, he has retreated into an almost hermitlike seclusion, largely hidden from public view and spotted only when he drops his two daughters off for school or goes for a workout at the gymnasium in a friend’s apartment building.