Phil Elvrum became involved in the Washington music scene while working at The Business, a record store in his home town of Anacortes, in the mid-1990s. Elvrum began experimenting with recording equipment in the back of the store, which led to the store's owner Bret Lunsford releasing two cassettes (Microphone and Wires and Cords) on his label, KNW-YR-OWN. Elvrum also played drums in Lunsford's band, D+, before moving to Olympia in 1997 to attend Evergreen State College.
Whilst in Olympia, Elvrum caught the attention of K Records owner and musician Calvin Johnson. After recording for some time at the Dub Narcoticstudios, Elvrum was able to complete his first full-length album, a CD entitled Tests, which was released in 1998 on Elsinor Records. Tests combined songs from his earlier cassette releases and the recently recorded Dub Narcotic recordings. At the same time, Elvrum released his first 7" single, "Bass Drum Dream" on Up Records.
Elvrum slowly gained recognition as a talented producer and recording engineer in the studio. While helping, often anonymously, with many of the area's artists, he began work on his second full-length, Don't Wake Me Up, released on K Records in 1999. Elvrum toured for a few months following the release with fellow K Records artist Mirah, and, showcasing his talents on the road, was able to build a small but loyal fanbase and gain appreciation in the indie music scene. While performing in another K Records band, Old Time Relijun, Elvrum began recording It Was Hot, We Stayed in the Water. Released on K Records in 2000, the album was Elvrum's most ambitious yet, featuring layers of harmonic guitars, noise, and Beach Boys-esque harmonies.
Elvrum's next release was a double album, entitled The Glow Pt. 2. Released by K Records in 2001, The Glow Pt. 2 was noted by critics for its production and songwriting. Probably his best-known album, it explored intensely personal themes, recalling lost loves and childhood memories. Sometimes sad, simple, and gentle ("I Felt Your Shape"), other times intense and layered with noise, guitars, and drums ("The Moon"). Pitchfork Media named The Glow Pt. 2 as the top album of 2001, and #73 on their 200 Top Albums of the 2000s. Tiny Mix Tapes named it the 5th best album of the 2000s.
After a lengthy tour of Europe and North America (known as the "Paper Opera Tour"), Elvrum returned to Dub Narcotic to begin work on his follow-up to The Glow Pt.2. Released by K Records in 2003, Mount Eerie was named after the mountain on Fidalgo Island where Elvrum spent much of his childhood. Containing five long songs, the album features a narrative arc, in which Elvrum dies, is eaten by vultures, and discovers the face of the Universe. It represents a turning point and a realization period in Elvrum's life. Like its predecessor, Mount Eerie was also praised by critics for its ambitious and imaginative production.
Elvrum toured North America and Europe again in 2002, playing mostly solo shows (billed as the "I Will Move Away Forever and Never Come Back Ever" tour) before settling in Finnkonevika, Kjerringøy, Norway, where he spent the winter living in a log cabin. In February 2003, he toured Japan with Calvin Johnson, Kyle Field, and the Tokyo band Moools, which resulted in the album Live in Japan. The album was credited to "The Microphones", with quotation marks to suggest that Elvrum was transitioning between musical projects. Live In Japan was released by K Records in early 2004, by which time Elverum had already begun to perform shows under the name Mount Eerie.
In January 2007, a one-off 7" single was released under the Microphones moniker, titled Two Songs by the Microphones. In 2008, The Glow Pt. 2 was reissued by K Records with an additional disc of outtakes and rarities. In March 2011, Elv(e)rum re-recorded the Microphones' song "I Lost My Wind" for the compilation Collaborate With a 1940's Wire Recorder. In 2013, the Microphones' four studio albums (in addition to the singles compilation Song Islands) were remastered and reissued on Elverum's own label, P.W. Elverum & Sun, Ltd.. In 2016, a compilation of the Microphones' early cassette releases was released as Early Tapes: 1996-1998.