The song reached the top of the charts in Australia, Canada, and the US.
"Bad Guy" is mostly an electroscopic song but features a trap music breakdown in the last 33 seconds of the song. It features finger snaps and clicks throughout the song.
On July 11, 2019, Eilish released a remix of the song with Canadian singer Justin Bieber. He tweeted, "Remix" a few days before this version's release.
On August 19, 2019, Billboard announced that "Bad Guy" had reached the top of the Hot 100 in the US, after spending nine weeks at number two. This made Eilish the first artist born in the 21st century to get a number-one song.
At the 62nd Annual Grammy Awards on January 26, 2020, the song won Record of the Year and Song of the Year. It was nominated for Best Pop Solo Performance but lost to "Truth Hurts" by Lizzo.
↑"ČNS IFPI" (in Czech). Hitparáda – Radio Top 100 Oficiální. IFPI Czech Republic. Note: Change the chart to CZ – RADIO – TOP 100 and insert 201930,31 into search. Retrieved July 29, 2019.
↑"ČNS IFPI" (in Czech). Hitparáda – Digital Top 100 Oficiální. IFPI Czech Republic. Note: Change the chart to CZ – SINGLES DIGITAL – TOP 100 and insert 201914 into search. Retrieved April 8, 2019.
↑"ČNS IFPI" (in Slovak). Hitparáda – Radio Top 100 Oficiálna. IFPI Czech Republic. Note: insert 201944 into search. Retrieved November 5, 2019.
↑"ČNS IFPI" (in Slovak). Hitparáda – Singles Digital Top 100 Oficiálna. IFPI Czech Republic. Note: Select SINGLES DIGITAL - TOP 100 and insert 201914 into search. Retrieved April 9, 2019.