K.Flay is also known for collaborating with artists such as Dune Rats, Grandson, Mike Shinoda, Party Favor, Tom Morello, Travis Barker, Vic Fuentes, and X Ambassadors.

Flaherty's parents divorced when she was seven years old and her mother soon remarried, bringing in a stepbrother and a stepsister, with her stepfather later adopting her.

[2] When she was 14 years old, her biological father died of undisclosed causes related to his alcoholism; many of her songs include references to him.

[4] K.Flay began her music career in 2003, believing that most hip hop hits on the radio were "simplistic, misogynistic and formulaic".

[7] She then independently released the now-unavailable mixtapes [appetite whetting 2.0] and MASHed Potatoes, as well as the EP Single and Famous with MC Lars.

[9] K.Flay signed with RCA Records in 2012, releasing two more EPs, Eyes Shut in 2012,[10] with songs produced by Liam Howlett from the British band the Prodigy,[11] and What If It Is in 2013.

In late April 2014, K.Flay announced[14] the release of her album Life as a Dog, by offering fans the ability to pre-order via PledgeMusic, reaching 196 percent of her initial goal.

The single was praised by Taylor Swift, who added "It's Strange" as one of her "Songs That Will Make Life Awesome" list[21] and was featured on the FIFA 16 soundtrack.

The EP's song "Blood in the Cut" appeared on the soundtrack for XXX: Return of Xander Cage,[25] Netflix's original series "Peaky Blinders", as well as BoJack Horseman (season 4, episode 6),[26] and in a 2017 NFL promo commercial drive.

[29] She was the opening act for the North American and European legs of Imagine Dragons' Evolve Tour.

[32] On March 1, 2019, K.Flay announced that she was working on her third studio album and released a lyric video for its first single, "Bad Vibes".

[41] A second single, "TGIF" featuring Tom Morello of Rage Against the Machine on guitar, was released with an animated visual on May 21.

[42] Later in 2021, K.Flay began livestreaming on Twitch; she uses the platform to interact with fans, host live interviews with other musicians, and create and mix original songs in real time.

This was her first release since suffering from a viral infection earlier in the year, which caused her to experience sudden sensorineural hearing loss and labyrinthitis and ultimately led to complete deafness in her right ear.

[48] On June 6, K.Flay announced that her upcoming album would be called Mono and revealed its cover, track list, and release date.

[51] On November 12, K.Flay released the EP I'm Making Friends With The Silence, containing softer versions of six songs from Mono inspired by her hearing loss.

[52] K.Flay has cited a wide range of musicians such as Royal Blood, Missy Elliott, Garbage, Lauryn Hill, Tame Impala, Jeremih, Metric, M.I.A., OutKast, Liz Phair, Cat Power, and Shlohmo as influences.