His father's staunchest defender: The life of Donald Trump Jr.

Donald Trump, Jr., the president's eldest son, has always been the most detail-oriented, business-focused child, leaving the spotlight to his father and his sister, Ivanka.

"I know the entertainment stuff helps us," he told Forbes in 2006. "But somebody's got to stay here to remind everybody that we build buildings."

Today, Jr. is the one in charge of building those buildings, now leading The Trump Organization with his brother, Eric.

But his life hasn't been without drama, and he's always been one of his father's staunchest defenders. Now embroiled in the latest Russia revelation, many are wondering more about Jr. Here's what we know: