DataGridTemplateColumn을 소트 하려면 SortMemberPath를 지정해주면 된다.
<DataGridTemplateColumn Header="기사명" Width="80" SortMemberPath="DRIVER">
<DataGridTemplateColumn.CellTemplate>
<DataTemplate>
<Grid>
<Image Width="6" Height="6" VerticalAlignment="Top" HorizontalAlignment="Left" Source="{Binding DRIVER_MEMO_IMG,TargetNullValue={x:Null}}"/>
<TextBlock Margin="4 0 0 0" Text="{Binding DRIVER}"/>
</Grid>
</DataTemplate>
</DataGridTemplateColumn.CellTemplate>
</DataGridTemplateColumn>