[1] He performed lead vocals on three of Chicago's biggest hits of the 1980s, 1984's "Hard Habit to Break" and 1988's "Look Away" and "I Don't Wanna Live Without Your Love".

During live shows, he sang the lower, baritone, vocal parts originally performed by founding guitarist Terry Kath, who had died in 1978.

[citation needed] He started a band called The Opposite Six while at Tamalpais High School in Mill Valley, California.

The band achieved a significant degree of acclaim as an opening act for many popular performers of that time, and recorded one album, ultimately released in 2005 "Flashback".

[6] This work allowed Champlin to become acquainted with other in-demand session men such as Jay Graydon, David Foster, and Steve Lukather (of Toto).

Among other artists that he worked with were Al Jarreau, George Duke, Boz Scaggs, Elton John, The Tubes, Lee Ritenour, Amy Grant, and Nicky Trebek.

[10] He and second wife, singer/songwriter Tamara Champlin, were part of the Scandinavian tour headlined by Leon Russell that also featured Joe Williams and Peter Friestedt.

[12] From 2014 to 2017 he performed several acoustic shows with Tamara Champlin in the U.S., Europe, Japan, and South and Central America, where they joined the Rock Pack Tour,[13][14] guested with California Transit Authority featuring Danny Seraphine,[15] played concerts to benefit Eddie Tuduri's Rhythmic Arts Project with the Pockets.

The last was a live recording of songs from his career, and included musicians Greg Mathieson, Jerry Lopez, Eddie Garcia, Tom Saviano, and Rochon Westmoreland.

In January, 2021, Champlin's solo album Livin For Love was released by Imagen Records and featured Champlin on keyboard and guitars as well as players Bruce Gaitsch, Carmen Grillo, Steve Porcaro, Vinnie Colaiuta, George Hawkins Jr., Greg Mathieson, Gordon Campbell, Lenny Castro, Marc Russo, Alan Hertz, Tal Morris, Jason Scheff, and Abraham Laboriel.

In early 1981, Champlin collaborated with Chicago's drummer, Danny Seraphine, by singing some backgrounds with Peter Cetera on a non-Chicago project.

1984's Chicago 17 enhanced Champlin's presence in the group, when he wrote several songs ("Please Hold On" and "Remember the Feeling") and sang (with Cetera) the hit single "Hard Habit to Break".

In 1988, Champlin's voice appeared prominently on several major hit singles from Chicago 19: "Look Away", "I Don't Wanna Live Without Your Love", and "You're Not Alone".That year, he also sang the theme to the television show In the Heat of the Night.

[22] In 1990, Champlin wrote, produced, and sang lead on "Hearts in Trouble", a song for the movie soundtrack of Days of Thunder.

As a result of the tour, a Live DVD/CD, recorded in Gothenburg on March 25, 2012, was released under the name "Bill Champlin Joseph Williams Peter Friestedt *All Star Band*" and hit the top of the Swedish charts.