The Chargers traded up to draft the Notre Dame linebacker with the 38th overall pick on Friday.
The 22-year-old told reporters: "I'm really excited to start this new journey in my life in San Diego. [I am] just excited to help us win a Super Bowl.
"My expectations are just to come in and do what I do. And that's study film, prepare, work hard and do my best to help this team win.
"It's the next chapter of my life, I'm just normal. Just like everybody else."
The 2012 Heisman Trophy finalist hit the headlines earlier this year when it was revealed that his recently-deceased girlfriend did not exist.