Chicago formed in Illinois, Chicago in 1967 as the result of a group of DePaul University music student's late night jams. After a short time as a successful professional covers band under the name The Big Thing - saxophonist Walter Parazaider, trombonist James Pankow, trumpet player Lee Loughnane, guitarist Terry Kath, keyboardist Robert Lamm, drummer Danny Seraphine, and bassist Peter Cetera started working on original material in 1968. The band signed to Columbia Records, changed their name to Chicago Transit Authority and released their self titled debut album in 1969.

Shortly after their debut album the band shortened their name to Chicago and released another self titled album – also known as Chicago II. The album vaulted into the top 10 in its second week on the Billboard chart along with the hit singles "Make Me Smile" and "25 or 6 to 4", the album quickly went gold and eventually platinum.

Chicago III was released at the start of 1971, just missing the #1 spot in the US while giving the band a third gold (and later platinum) LP. Also released in 1971, Chicago IV - a 4 disc live album recorded at Carnegie Hall hit the top 5, followed in 1972 by the release of Chicago V, which spent 9 weeks at #1 in the US. A year later Chicago VI was released, repeating the success of it's predecessor and launching the top 10 singles "Feelin' Stronger Every Day" and "Just You 'N' Me".

The next top 10 hit, "(I've Been) Searchin' So Long", was released in advance of Chicago VII in the late winter of 1974. The album was the band's third consecutive chart-topper and another million-seller. Chicago VIII - which marked the promotion of sideman percussionist Laudir de Oliveira as a full-fledged bandmember - appeared in the spring of 1975 and spawned the top 10 hit "Old Days," and became the band's fourth consecutive #1 LP. Chicago X missed hitting the #1 spot but eventually sold over 2 million copies, in part because of the inclusion of the internationally successful Grammy Award winning #1 smash "If You Leave Me Now". Chicago XI, released in the late summer of 1977 continued the seemingly endless string of success, reaching the top 10, selling a million copies, and generating the top 5 hit "Baby, What a Big Surprise".

Chicago suffered a crushing blow when on January 23rd 1978, guitarist and gun enthusiast Terry Kath passed away in a freak gun accident. Replacement guitarist Donnie Dacus debuted on the non-numerical titled Hot Streets. The sound of Hot Streets, as indicated by the first single - the top 20 hit "Alive Again" - was a move towards a harder rock sound.

A couple of albums later, a few line-up changes and with the direction now focused on the band's talent for power ballads sung by Cetera, the band signed with Full Moon Records, an imprint of Warner Bros., and released Chicago 16 in the spring of 1982. Prefaced by the single "Hard to Say I'm Sorry" - which topped the charts, leading to a major comeback - the album returned Chicago to million-selling top 10 status. Chicago 17, released in the spring of 1984 was even more successful - in fact, the biggest-selling album of the band's career. It spawned 2 top 5 hits, "Hard Habit to Break" and "You're the Inspiration."

This renewed success changed the long-established group dynamics, thrusting Cetera out as a star. He left the band for a solo career in 1985. Pinnick also left at about this time, and the band did not immediately bring in a new guitarist. As Cetera's replacement, Chicago found Jason Scheff, the 23-year-old bass-playing son of famed bassist Jerry Scheff, a longtime sideman with Elvis Presley. Scheff boasted a tenor voice that allowed him to re-create Cetera's singing on many Chicago hits.

Chicago 19 was released in the spring of 1988. Among its singles, "I Don't Want to Live Without Your Love" which made the top 5, "Look Away" topped the charts, and "You're Not Alone" made the top 10 as the album went platinum. Another single, "What Kind of Man Would I Be?," originally found on Chicago 19, was included as part of the 1989 compilation Greatest Hits 1982-1989 (which counted as the 20th album) and became a top 5 hit, while the album sold 5 million copies by 1997.

Chicago are one of the most successful American rock bands of all time, and have had an array of top 10 albums and singles all over the world. Chicago continue to release classic albums, and they tour frequently.