On the day before the Irish Language Act march in Belfast, Móglaí Bap went out with a friend of his and spray-painted the word "Cearta" on a bus stop.

was banned from the Irish-medium radio station RTÉ Raidió na Gaeltachta (RnaG) for "drug references and cursing".

The title references the drug MDMA: 3CAG means trí chonsan agus guta ('three consonants and a vowel'), slang for the substance.

[9] The release was retrospectively described in The Skinny as "an irresistible collection of raucous hip-hop that fused the Irish and English languages with a wicked sense of humour.

"[10] It was retrospectively described in The Guardian as "self-aware and swaggering in equal measure as it flipped between nights on the town to the everyday reality of growing up in post-Troubles Northern Ireland.

[12] In 2021 Kneecap released their single "MAM" as a tribute to their mothers; the song was acknowledged as a shift away from their usual style saying that they wanted to do something more "real".

[14] In early 2023, the group began filming a motion picture, also titled Kneecap, depicting a fictionalised account of their rise to fame.

[20] The 2024 biopic film Kneecap, in which the band members play themselves alongside more experienced actors including Michael Fassbender, Josie Walker, and Simone Kirby, is set in the West Belfast Gaeltacht Quarter in 2019.

The group critiques the PSNI, the UK government, and political figures like Arlene Foster, often highlighting issues such as class inequality and working-class struggles.

Kneecap’s approach combines political commentary with social issues, and their music often addresses themes like addiction and mental health.

[29] In 2020 Kneecap publicly supported an independent Palestine by flying Palestinian flags at concerts and pledging to boycott the State of Israel.

[25][26] The Guardian has suggested that Kneecap's earlier work focused on asserting Gaelic identity and merging it with hood culture.