Ha! I can one-up you there. I have a great-great-grandpa who served on BOTH sides of that war. :-) :-)
Or you could say he served in two wars: The first - 1861-1863 - was the War Between The States, aka Mr. Lincoln's War, aka The War of Northern Aggression, aka the Second American Revolution, etc etc etc. And the second war he fought in - from 1863-1865 - was the Civil War, aka The Late Great Rebellion, aka The War of Southern Aggression, etc etc.
And all because his hometown on the Arkansas/Mizoo border switched loyalties mid-war, while he was in a Union POW work-camp.
Yup! I've got all kinds of famous ground-breaking ancestors. On the other side of my family, I have a great-great-grandma & grandpa who were the very first ever to get divorced in their particular branch of the Mennonites.
Just bursting with pride here..... :-)
Or you could say he served in two wars...
Well, truth be told, my G-G-G grandpappy did fight in the Civil War and the Mexican American war. Spent some time in a Mexican prison for his troubles, I might add. It's why his son, my G-G grandpappy was born here in Texas, just prior to statehood.