"I hope that such a military conflict between the North and the South never happens again," Song said about the shooting.
The soldier's statements were in stark contrast to the rhetoric of North Korea's state-run news agency, which has threatened "full-scale war" if the county's territory is violated by any military maneuvers.
In its defense of the fatal Nov. 23 shooting, North Korean officials said Saturday that it was "regrettable, if it is true, that civilian casualties occurred," although it blamed South Korea for creating a "human shield" by having civilians near artillery positions.
Two civilians and two South Korean marines were killed in that shooting on Yeonpyeong Island.
South Korean officials told lawmakers that the North is likely to strike again.
Meanwhile, the Chinese foreign minister has called on all parties to avoid acts that further risk inflaming the situation on the Korean peninsula.
It's the highest level comment yet from the Chinese regarding the deadly shooting.
China has issued no direct public criticism of North Korea since last week's incident.
Beijing has said it is concerned U.S.-South Korean naval drills, which were scheduled to end Wednesday, could lead to further violence.
The Associated Press Contributed to this report.