John Sidney "Jack" McCain IV is Sen. John McCain's eldest biological son, born in 1986. Inspired by his father's dedication to his country, Jack applied to the Naval Academy right out of high school. According to Town & Country, this was the only school that Jack applied to. "I want to be a part of my family's legacy," Jack said, according to The New York Times. The young man quickly rose through the ranks, carrying the family's tradition and becoming an MH-60 Seahawk helicopter pilot.

In 2013, Jack married Renee Swift (via Heavy). In 2016, the couple welcomed their first child, John S. McCain V, aka "Mac." When his father was sick, Jack was deployed in Afghanistan. He rushed home, and while waiting for his second flight at an airport in Doha, Jack received the news that his father had died. "It was surreal to kind of watch people crowding around the television in the airport to look," McCain told The Washington Post. "There's not much you can say at that point. I got on the aircraft and flew home." 

During the private burial service, Jack delivered the eulogy. "Goodbye, Old Man," he said. "Like you, I believe we'll see each other again. Until then, I'll keep your faith, and make my life count for something more than myself, so that you'll be proud of me on that day."

Along with his wife Cindy and seven children, John McCain is survived by five grandchildren.