Chicago 17

The biggest seller

Chicago 17 came out on 14 May 1984 on Full Moon/Warner Bros. and was the band's second album produced by David Foster. It remains their best-selling album, with more than 6.1 million copies sold in the United States, the United Kingdom and Japan as of 2023, and has been certified six times platinum by the RIAA. Four singles came from it, and all reached the top 20 of the Hot 100. Session players joined the band on the record, and Jeff Porcaro played uncredited drums on the first track.

At the 1985 Grammys Foster won Producer of the Year, Humberto Gatica won for engineering, and Foster and Jeremy Lubbock won for the instrumental arrangement on Hard Habit to Break. The cover shows a brown paper package tied with twine, with the Chicago logo showing under the wrapping. Cetera's brother Kenny sang backing vocals and toured with the band for the 17 tour. Cetera left the following year.