Focused on American roots music, Rounder's catalogue of more than 3000 titles includes records by Alison Krauss and Union Station, George Thorogood, Tony Rice, and Béla Fleck, in addition to re-releases of seminal albums by artists such as the Carter Family, Jelly Roll Morton, Lead Belly, and Woody Guthrie.

The three shared an apartment as well as a desire to bring roots music to a wider audience, and began to explore the idea of starting a record company.

[7] "We were all involved in radical politics, and the anti-war movement, and a lot of our inspiration for starting Rounder had to do with minority culture and wanting to represent music that we really liked, but that was not in the mainstream," Levy said in a 2015 interview.

[9] Levy, Irwin and Nowlin also self-identified as "Rounders", the name reflecting the "outlaw self-image of three romantics who positioned themselves in opposition to capitalism, the programmatic rigidity of the old Left, and the more doctrinaire cultural rules of the folk revival itself.

Rounder 0002 was by the Spark Gap Wonder Boys; a local band, the album was recorded at the Harvard and MIT radio stations for "the cost of the tape."

[14] By 1974, Rounder had put out 22 records, including the label's breakthrough album, Norman Blake's Home in Sulphur Springs.

[19] In the mid-1970s, with a catalog of about 200 LPs by acoustic artists, the label expanded its Bluegrass focus to include folk, blues and other styles of music, notably signing NRBQ, Arlen Roth and George Thorogood and the Destroyers.

[21][11] Irwin described Thorogood's success as a "watershed" moment for Rounder, stating that while it did not change the founder's interest or mission, it made clear that the label needed to expand both its staff and its distribution.

[24] In the early 80s, Rounder once again broadened its focus, establishing a reggae imprint, Heartbeat and adding Klezmer, Cajun, Zydeco and Tex-Mex Conjunto musicians to its roster.

[13] Throughout the decade, the label released records by esoteric artists who were unlikely to garner mainstream recognition, including Ted Hawkins, Jonathan Richman, and Sleepy LaBeef.

Among others, the acquisition brought Utah Phillips, Dave Van Ronk, Christine Lavin, and singer-songwriter Nanci Griffith to the label.

He first heard Alison Krauss in 1984 on a demo of the band Classical Grass, later known as Union Station, and Krauss—who mainly played fiddle and contributed vocal harmonies—sang lead on a gospel song.

[32] In 1991, producer Ron Levy partnered with Rounder to create and distribute the Bullseye Blues label, releasing music from Lowell Fulson, Smokin' Joe Kubek and Charles Brown.

[33] In the winter of that year, the company merged with Rykodisc distribution's East Side Digital to form REP Co. along with Precision Sound.

The label, founded in 1974 by Rounder associate Bruce Kaplan, had a catalog of over 500 records by artists including Sweet Honey in the Rock, Pete Seeger, and Doc Watson at the time of its acquisition.

Artists including Blake Babies, Juliana Hatfield, Kay Hanley and Sarah Harmer released records on the imprint.

Expected to increase the sales of new releases of artists such as Juliana Hatfield, the PolyGram Group Distribution affiliate handled more than a third of Rounder's titles.

[51][52] Echoing the early achievements of Hazel Dickens and Alison Krauss, in the male-dominated field of bluegrass music, in 2007 Rounder released Crowd Favorites, a compilation of six albums by Claire Lynch.

[56][57] The same year, the label launched what would become a 100-disc reissue series compiled by musicologist Alan Lomax whose archival project began in 1938 with the taping of Jelly Roll Morton, and ultimately included Lead Belly, Muddy Waters, Woody Guthrie, and many others.

[59] Releasing about 100 albums per year by the end of the decade, Rounder's catalog had grown to include Del McCoury, David Grisman, the Whitstein Brothers, Madeleine Peyroux, and James King, as well as supergroups Dreadful Snakes (Jerry Douglas, Pat Enright, Bela Fleck, Mark Hembree, Blaine Sprouse, and Roland White) and Longview (Dudley Connell, James King, Don Rigsby, Joe Mullins, Glen Duncan, and Marshall Wilborn), and the compilation Oh Sister.

[60] Artists including Robert Plant, Dolores O'Riordan, Ann Wilson, Fleck, Minnie Driver, Rush, Cowboy Junkies, Griffith, Laura Nyro, Fairport Convention, Linda Thompson, Boz Scaggs, Nelson, Skaggs, and Joe Diffie among others, recorded for Rounder during the 2000s.

Broadcast on PBS in March 2010, The Rounder Records 40th Anniversary Concert was released on DVD to benefit NARAS's Grammy in the Schools Program.

Founded in the late 1970s, the Sugar Hill catalog included records by Ricky Skaggs, Lee Ann Womack, Sarah Jarosz, Liz Longley, Corey Smith, Kasey Chambers, Sam Bush, moe., and Bryan Sutton and Black Prairie.

[65] John Strohm, a musician and entertainment lawyer, became Rounder's president in 2017, as Virant moved to a senior creative role.

[66] A guitarist, drummer, and songwriter, Strohm spent half of his career playing in critically acclaimed alternative bands including the Blake Babies, Antenna, and the Lemonheads.