Figures from opinion pollsters Demoskop show support among voters aged 55 or over has gone from 26 percent to 41 percent.
The survey compared voter confidence in April just after the resignation of former head Håkan Juholt to today.
Among middle class wage earners, confidence in the until-recently beleaguered left-of-centre party has gone from 21 to 34 percent.
Expressen notes that this group has been key to the right-of-centre government's election victories and could be crucial to the Social Democrats' survival on ballot day.
Not all groups have been equally swayed by the stabilising effect seen by the former Metal Union head's appointment to the post.
"We must consider how to get younger professionals in the cities to also see us as an alternative," Löfven tells Expressen.