I believe Kerry took his wife to Paris for their honeymoon. While there, he met with Madame Binh and brought back a peace treaty or whatever to present to the Senate. He spent a lot of time negotiating deals. Nixon hated him for his interference for obvious reasons.
Hawaiian, see Jaidyn's comment.
I will add that, when he was in Paris meeting with Madame Binh he DID NOT meet with the U.S. negotiators---I'm don't believe he informed them of his "efforts".
Lastly, as he was doing this, he was an officer in the U.S. Navy. Perhaps the reserves, but an officer nonetheless.