Jason Morelli
From Halopedia, the Halo wiki
Jason Morelli aka The Castaway is Jersey Morelli's father[1], a signalman in the Navy, has been away for over a year and a half. He is attached to Naval Intelligence, Radio Beacon Deployment Program, current tour of duty 513 days as of the date that Durga is found by Jersey Morelli. Likes classical/jazz music.
When Reach was glassed, Jason was assigned to a ship named the UNSC Soberg on a deep-space reconnaissance assignment.[2]
In a live telephone call on October 19,2004 Melissa confirmed that Jason is, in fact, the man she refers to as the The Castaway.
He met Bonita Morelli on the Churchill Ferry in New York. Where he dazzled her by talking about music from the 1940s.[3]
References
Partial transcript of Jersey.wav
Durga: ...Give me a target Jersey: Me Durga: Lock Jersey: What's my name? Durga: Jersey Morelli... Jersey: DAMN! Durga: Father Jason is a corporal in the signal core attached to Naval intelligence, Radio beacon deployment program. He left you the material currently playing over this room's audio servers.