A native of Mount Desert island, Longfellow is old enough to remember the days when the radioactive fog covered almost the entire island. His indomitable will and fit physical structure still manage to keep up with his old age.
Old Longfellow is a seasoned hunter who can recall a fairly large portion of the region's history; from desperate struggle to hubris. Taking the fog's retreat for granted. Longfellow is a veritable legend in Far Harbor circles and one of the few guides capable of guiding a person safely through the fog. His age and experiences made him cynical and he hits the bottle of whiskey a bit too often in recent years.
Longfellow absolutely hates the Children of Atom. When he was a young man, he fell in love with a girl named Hannah. The feeling was mutual and the two planned a future together, however it was cut short when the Children of Atom's solders attacked the pair at their hideaway deep within the fog. Left for dead, Longfellow eventually made it to civilization. It took two months to recover for the hunter to recover from his injuries. By then it was too late for Hannah; Atom's zealots warped Hannah's mind, and turned her to their ways. The child she carried was stillborn, due to the radiation she was exposed to. By the time she fell victim to the insane trappers that roam the island, Longfellow was well on his way to becoming an embittered shell of a man, mostly regretting the death of his child.
Longfellow is a heavy drinker, often asking if the Sole Survivor can stop for a drink or, when trading, if he can be provided with alcohol and even he will openly state that he would like to have a drink after his death stating that he would celebrate his death with a final toast. (if the player kills him.)
Despite the fog driving most people insane (such as the Trappers), Longfellow seems to be quite sane and reasonable—though he often claims his limbs are stiff and his bones ache due to the exposure of the fog.
Longfellow openly dislikes the Children of Atom; disliking if the Sole Survivor joins them and when talking with DiMA when he talks about the possibility of there being peace with them, he openly states he would enjoy fighting them. Interestingly, he disapproves if the Sole Survivor suggests to spare or reason with Sister Gwyneth when talking to Grand Zealot Richter in The Heretic mission. This is possibly he dislikes sparing a Child of Atom, even if that is the order of another Child of Atom.
When Idolized, he will reveal he always wanted a son and/or daughter to teach what he has learned to them.
He will become hostile if Far Harbor is destroyed.
He is not resistant against radiation.
He will sometimes sing the traditional Irish songs "Wild Rover," "Molly Malone," and "Jug of Punch" when idle.
Sometime when picking up junk items, he will jokingly question why you'd need something 3 times older than himself. Since by the events of Far Harbor took place 210 years after the Great War, which would be around the same time the last of most pre-war junk was made, that would put Old Longfellow at around 70 years old.
While utilizing power armor does not negatively affect Old Longfellow's opinion of the player character as it does for Strong, he will state he's not overly fond of powered armor because "It's too damn loud to hunt in".
He can be killed if the player chooses to shut off the wind farm by first warning the player to leave the fuses required to open the door leading to the terminal then immediately turning hostile when the wind farm is down.
The following is based on unverified behind the scenes information and has not been confirmed by canon sources.
Old Longfellow may be a reference to the Maine-born poet Henry Wadsworth Longfellow, whose appearance was similar. The real Longfellow died in Cambridge, Massachusetts, and also had a wife who suffered a miscarriage.
End of information based on unverified behind the scenes information.