Smyth was born in Ballyhooly Co. Cork. He was the last Union General to be killed in the Civil War. He died on the day of Lee’s surrender at Appomattox, having been mortally wounded by a sniper two days previously. He fought at Antietam, Fredericksburg, Chancellorsville, and was a Brigade Commander at Gettysburg. Following his death, he was posthumously brevetted Major General, US Volunteers.