Lonely Runs Both Ways was released in 2004, and eventually became another Alison Krauss & Union Station gold certified album. Ron Block described Lonely Runs Both Ways as "pretty much... what we've always done" in terms of song selection and the style in which those songs were recorded.[citation needed] Krauss believes the group "was probably the most unprepared we've ever been" for the album and that songs were chosen as needed rather than planned beforehand. She also performed a duet with Brad Paisley on his album Mud on the Tires in the single "Whiskey Lullaby." The single was quite ranked in the top fifty of the Billboard Hot 100 and the top five of the Hot Country Songs, and won the Country Music Association Awards for "Best Musical Event" and "Best Music Video" of the year.[citation needed]

Krauss recorded a collaborative album, Raising Sand with Robert Plant in 2007 which would ultimately be RIAA certified platinum. Raising Sand was nominated for and won 5 Grammys at the 51st Grammy Awards including Album of the Year, Best Contemporary Folk/Americana Album, and Record of the Year ("Please Read the Letter"). Krauss and Plant recorded a Crossroads special in October 2007 for the Country Music Television network which first aired on February 12, 2008. The pair are currently working on a new album.

Krauss has made multiple guest appearances on other records with lead vocals, harmony vocals, or fiddle playing. In 1993 she recorded vocals for the Phish song "If I Could" in Los Angeles. In 1997 she contributed harmony vocals in both English and Irish to Irish traditional band Altan's Runaway Sunday album. She has contributed to numerous motion picture soundtracks, most notably the soundtrack O Brother, Where Art Thou? in 2000. She and co-vocalist Dan Tyminski contributed multiple tracks to the soundtrack, including "I'll Fly Away" (with Gillian Welch), "Down to the River to Pray", and "I Am a Man of Constant Sorrow."[citation needed]

In the film, Tyminski's vocals on "I Am a Man of Constant Sorrow" were used for George Clooney's character. The soundtrack sold over seven million copies and won the Grammy for Album of the Year in 2002.[citation needed] The unexpected success of the album has been partially credited, as was Krauss herself, with bringing a new interest in bluegrass to the United States. She has said, however, that she believes Americans already liked bluegrass and other less-heard musical genres, and that the film merely provided easy exposure to the music. She did not appear in the movie, at her own request, as she was nine months pregnant during its filming.

In 2007, Krauss released the anthology A Hundred Miles Or More: A Collection which was a collection of soundtrack work, duets with artists such as John Waite, James Taylor, Brad Paisley and esteemed fiddle player Natalie MacMaster, and newer tracks.[citation needed] The album was very commercially successful, but was received with a lukewarm reception from critics.[citation needed] One of the tracks, "Missing You", a duet with Waite (and a cover of his hit single from 1984), was similarly received as a single.[citation needed] On August 11, television network Great American Country aired a one-hour special, "Alison Krauss: A Hundred Miles or More" based on the album and featured many of the album's duets and solo performances.[citation needed]

Other soundtracks for which Krauss has performed include Twister, The Prince of Egypt, Eight Crazy Nights, Mona Lisa Smile, Divine Secrets of the Ya-Ya Sisterhood, Alias, Bambi II and Cold Mountain. She also contributed the song "Jubilee" to the 2004 documentary Paper Clips. The Cold Mountain songs "The Scarlet Tide" by T-Bone Burnett and Elvis Costello, and "You Will Be My Ain True Love", by herself and Sting were nominated for an Academy Award, and she performed both songs at the 76th Academy Awards, the first with Costello and Burnett and the other with Sting. She also worked as a producer for Nickel Creek on their debut self-titled album in 2000 and the follow-up This Side in 2002, which won Krauss her first Grammy as a music producer.[citation needed]

Krauss's earliest musical experience was as an instrumentalist, though her style has grown to focus more on her vocals with a band providing most of the instrumentation. Musicians she enjoys include Lou Gramm of Foreigner and Paul Rodgers of Bad Company. Krauss' family listened to "folk records" while she was growing up, but she had friends who exposed her to groups such as AC/DC, Carly Simon, The Rolling Stones, Lynyrd Skynyrd, and ELO. She cites Dolly Parton, with whom she has since collaborated a number of times, as a major influence. Some[who?] credit Krauss and Union Station, at least partially, with a recent[when?] revival of interest in bluegrass music in the United States. Despite being together for nearly two decades and winning numerous awards, she said the group was "just beginning right now" (in 2002) because "in spite of all the great things that have happened for the band, [she] feel[s] musically it's just really beginning." Although she alternates between solo releases and works with the band, she has said there is no difference in her involvement between the two.

As a group, AKUS have been called "American favourites," "world-beaters," and "the tightest band around." While they have been successful as a group, many reviews note Krauss still "remains the undisputed star and rock-solid foundation" and have described her as the "band's focus" with an "angelic" voice that "flows like honey". Her work has been compared to that of The Cox Family, Bill Monroe, and Del McCoury,[citation needed] and has in turn been credited with influencing various "Newgrass" artists including Nickel Creek, for which she acted as record producer on two of their albums. In addition to her work with Nickel Creek, she has acted as producer to the Cox Family, Reba McEntire and Alan Jackson. Adam Sweeting of The Guardian has said Krauss and Union Station are "superb when they stick to hoedowns and hillbilly music, but much less convincing when they lurch towards the middle of the road," and Blender magazine has said the "flavorless repertoire [Krauss] sings... steers her toward Lite FM". In addition, Q magazine and The Onion AV Club have said their newer releases are "pretty much the usual," and that although Krauss is generally "adventurous," these recent releases contain nothing to "alienate the masses".

Krauss generally sings as a soprano[citation needed] with little to no vibrato: her clear vocals have been described as "angelic". She has said her musical influences include J. D. Crowe, Ricky Skaggs, and Tony Rice. Many of her songs are described as sad, and are often about love, especially lost love. Krauss herself has said of her song selection that she looks for "tunes that [she] can relate to".[citation needed] Though she has a close involvement with her group and a long career in music, she rarely performs music she has written herself. She has also described her general approach to constructing an album as starting with a single song and selecting other tracks based on the first, to give the final album a somewhat consistent theme and mood. She most commonly performs in the bluegrass and country genres, though she has had two songs on the adult contemporary charts, has worked with rock artists such as Phish and Sting, and is sometimes said to stray into pop music.