Sheppard is an American soldier and the first official commander of UNGDI. He is a decisive, charismatic leader, determined to put a stop to Nod.
He has a son, Logan Sheppard, who is also in GDI, as a commando. His son often has to put up with other troopers' hostility due to him being a general's son.
During the campaign, Sheppard is forced to serve GDI as a political leader instead of a purely military capacity. The most notable example is the UN inquiry into GDI's supposed atrocities in Poland. Nonetheless, Sheppard manages not only to blunt Kane's media offensive but also secure new funding from the United Nations and direct a vigorous counter-offensive against Nod, eventually driving the Brotherhood back to Kane's temple in Sarajevo.
We've found him, Commander- Kane's temple and base of operations. This field operative's covert transmission came to us live just five minutes ago, so there's no doubt that Kane's inside. He's surrounded himself with his own crack militia. Getting to him... won't be easy. Ironic, isn't it? Kane's planted his temple just outside of Sarajevo. If that sounds familiar, it's because that's where another madman started World War I. And here we are, trying to stop this madman from doing it again. Commander, there is to be no quarter given. No leniency in dealing with Kane and his zealots. Wipe his temple off the face of the earth. Destroy the bastard... or prepare to... die trying. - Sheppard to Solomon
Behind the scenes
General Mark Sheppard was played by Las Vegas actor Eric Alan Martin, who passed away on 1 April 2019.
General Sheppard’s rank and stars apparently do not match up by United States military standards: Sheppard has three stars per shoulder pad, which by US standards would make him a Lieutenant General. These errors may be explained if Sheppard is actually wearing a GDI uniform that may just resemble a US uniform. In that case, the ranking structure and awards (such as the aiguillette) could be unique to GDI and not necessarily follow the US pattern - as evidenced by the inclusion of Commander and Lieutenant Commander ranks within the traditional GDI army. It is also possible that Sheppard held the rank of Brigadier General in the US Army, and his new position came with a provisional promotion to Lieutenant General.
An oversight by Westwood Studios had his last name officially spelled as both "Shepherd" and "Sheppard" within the Command & Conquer manual.