I completed the main quest before I joined the Stormcloaks and did the Civil War quest and did not receive the "War Hero" achievement. "Taking Sides" and "Hero of Skyrim" came up just fine but I was never sent to capture Fort Sungard or Fort Greenwall.

Im having the same problem. This is absolute BS. When you do the main quest, and give the storm cloaks Fort Sungard, you should get the achievement.

I joined the stormcloaks, then did the storyline, and STILL didn't get the War Hero Achievement. Not very happy. its the ONLY achievement i have left to get. B***S***!!!!!! i have to replay the game for this one stupid achievement WHICH I SHOULD ALREADY HAVE GOTTEN. Disappointing Bethesda