He also limped slightly while walking into the auditorium in what is believed to be an aftereffect from the stroke.
Kim's appearance comes amid increasing tensions due to the North's intensifying nuclear standoff with the world.
New conflicting reports have also emerged over a possible missile launch by Pyongyang.
Last week, South Korea's JoongAng Ilbo newspaper reported that North Korea is "highly likely" to conduct missile tests early this month, citing an unidentified intelligence source.
But South Korea's Yonhap news agency carried a conflicting report hours later, saying there were no signs of any imminent missile launch.
North and South Korea are also holding a third round of talks on their troubled joint industrial complex, as well as the South's continued call to release a detained worker at the facility.
The talks in the North Korean border city of Kaesong, where the industrial complex is located, are taking place as US and Chinese officials meet in Beijing for talks on implementing UN sanctions against Pyongyang.
The talks in Kaesong, which began on Thursday morning, are expected to indicate whether the North will ease its demand for huge extra payments from Seoul now that it faces international sanctions.
The South Korean-funded Kaesong complex is a significant source of foreign currency for the impoverished North, which received $26m last year in wage payments.