The morning after Moe’s birthday dinner, I find Nielson hard at work, bouncing in an office chair in his basement, massaging a keyboard that’s tethered to his laptop. Empty bottles of Diet Dr Pepper fill a number of cubed shelves behind him. Walled in by old tape machines and guitars, Nielson is working on a remix of a song by his younger brother, Kody, whose original track is playing on a continuous loop. One after the other, Nielson adds various flourishes with instruments pulled from all corners of the room.

The Nielsons bought this home three years ago, after living briefly in a nearby yurt—a portable, one-room, high-ceilinged tent—with the midwife who helped Jenny birth Iris. They had originally come to Portland without a plan, except to start over. When Moe was born six years ago in a converted barn on Jenny’s family farm in New Zealand, Nielson was playing guitar in the Mint Chicks, a well-regarded but dysfunctional punk band he founded in 2001.

Nielson grew up in Auckland. His parents met in Los Angeles while touring behind John Rowles, a lounge singer beloved in New Zealand during the ‘70s. Nielson’s mother is a native Hawaiian, a gifted singer, pianist, and hula champion from Oahu. His father, a New Zealander, is a renowned horn player who exposed his two sons to the jazz of Miles Davis at an early age. To be half-Polynesian in New Zealand, Nielson says, is “to be the kid a shop owner will follow around. It’s like you’re walking into every situation at a negative 10, and you’ve got to work really hard to get to zero.”

Nielson faced just as much heartache at home. As a teenager, he began to experience crippling bouts of insomnia, the combined result—he thought—of his father’s long-running addiction to alcohol and heroin, and the fallout from his parents’ separation. Nielson would lie awake most nights, only to sleep through school the next day. But as part of his attempt to get clean and make amends, Nielson’s father supported his son in two pivotal ways: He helped him gain entrance to New Zealand’s most prestigious art school, Elam, by gathering recommendations from sympathetic teachers, and he bought him his first guitar. It was at Elam that Nielson, a painter, would meet Jenny, a sculptor. They moved in together within a few months of their first date. Playing music, which Nielson had long resisted, became a way of making use of all those sleepless nights.

With Kody as their frontman and Nielson as their de facto manager and guitarist, the Mint Chicks quickly gained renown in New Zealand, going on to release a handful of records. But as tensions rose between the brothers, the elder Nielson became more attuned to his new responsibilities as a father. A visit to an uncle in Portland inspired a more permanent move to the United States. And then a funny thing happened.

Upon landing in Oregon with his new family, Nielson—who had given up on the idea of playing music professionally—found work as an illustrator. But in his free time, he began to write songs, just for fun. Having worn out most of his record collection, he wanted to make the sort of odd and obscure psych-rock album that he couldn’t find. With just a cheap tape recorder, a guitar, and a single microphone, he recorded one song a night with no intention of releasing anything. “Breakbeats? Guitar solos? Weird voices? No one is going to think is cool at all or want to release it, so it doesn’t matter,” he says of his mindset at the time. “It was my own private thing—I kept it a secret.”

But in hopes of connecting online with other similarly specific songwriters, he decided to post his songs pseudonymously to a Bandcamp page. Not long thereafter, “Ffunny Ffrends”—a breezy, Zappa-like love song about two friends of his from high school—found its way to a growing number of mp3 blogs, and then, to his office. “Where did you get this song?” Nielson asked a coworker in disbelief, after the sound had wafted across the room. “‘Oh, my friend at Nylon magazine sent it to me,’” he remembers the guy saying. “‘Just some band that’s blowing up right now.’” Nielson says he had recorded the song just six days earlier.

Unknown Mortal Orchestra: "Ffunny Ffrends"

Within weeks, A&R reps at some of the world’s most influential independent record labels—including Domino, Matador, and XL—began to enthusiastically email the address attached to his Bandcamp account, asking to hear more. Nielson, convinced it was all an elaborate prank, had to decide whether or not he wanted to take another chance on music. “I’d given up the dream,” he says. “Jenny encouraged me to try again.”

A year later, in the summer of 2011, Fat Possum released UMO’s self-titled debut, which featured Nielson’s songs exactly as he originally recorded them. He formed a live band with friends from Portland and hit the road. Endless stretches of touring across the United States and Europe eventually gave way to the sort of rampant drug use he became wary of as a kid. He grew depressed and disillusioned, unable to keep it together when he came home. In 2013, he released II, an album of pensive, guitar-driven soul music that provided frequently troubling glimpses of his mental state. (That album’s opening line: “Isolation can put a gun in your hand.”) He was trying to build a body of work for his family, but he was behaving just as erratically as his father had before him. If he was going to make another album, it was going to surpass what he thought he was capable of making, if only for his family.