[4] He had an older brother, Rod Kath,[5][6] was raised in the Norwood Park neighborhood of Chicago,[7] and attended Taft High School.

[9] He acquired a guitar and amplifier when he was in the ninth grade, and his early influences included The Ventures, Johnny Smith,[10] Dick Dale,[8] and Howard Roberts.

[15] They were fired from the group, which wanted to merge with another band, Little Artie and the Pharaohs, while leader and guitarist Mike Sistack explained that "it's just business.

"[16] In 1966, Kath joined a cover band called the Missing Links,[8] taking Parazaider and Seraphine with him, and started playing clubs and ballrooms in Chicago on a regular basis.

[18] Kath's compatriot James William Guercio (who later became Chicago's producer) was lead guitarist in one of two road bands performing on The Dick Clark Show with the Missing Links.

[4][19] Kath received an offer from Guercio to play bass for the Illinois Speed Press and move to Los Angeles, but declined as he considered the guitar his main instrument and wanted to sing lead.

He stayed with Parazaider, Seraphine, and Loughnane instead,[20] who quickly recruited trombonist James Pankow from De Paul and vocalist/keyboardist Robert Lamm.

With the addition of singer and bassist Peter Cetera of The Exceptions, they moved to Los Angeles and signed with Columbia Records, renaming the band Chicago Transit Authority.

[23] He has been praised for his guitar skills and described by rock author Corbin Reiff as "one of the most criminally underrated guitarists to have ever set finger to fretboard".

[27] The album liner notes indicate that the nearly seven-minute piece was recorded live in the studio in one take, using only a Fender Dual Showman amplifier pre-amped with a Bogen Challenger P.A.

[29] The same album saw Kath collaborate with orchestral arranger Peter Matz on the four-part suite "Memories of Love", singing the lead vocal.

[31] He continued this style on the following year's Chicago XI, contributing the funky "Mississippi Delta City Blues" and the aggressive "Takin' It on Uptown", which counterbalanced some of the material other members were producing.

[32] After his death, to memorialize Kath and to commemorate the resumption of Chicago, the band composed and published the song "Alive Again" on its first album without him, Hot Streets.

[27] He also used a Gibson SG Standard, as pictured on Chicago Transit Authority's inner sleeve, and a Gibson SG Custom, and was one of the few well-known guitarists to make regular use of the 1969 Les Paul "Professional" model, which sported a pair of unconventional low-impedance pickups with a special impedance-matching transformer for use with a standard high impedance-input amplifier.

The standard blonde Telecaster had its black pickguard and its neck-position pickup removed, and the hole enlarged and fitted with a Gibson humbucker.

Among the re-discovered equipment was his "Pignose" Telecaster, an Ovation acoustic, a Fender Stratocaster, and a Gibson SG Custom with the pickups removed.

[39] Pankow, who wrote "Make Me Smile", tried rehearsing the song with various members singing lead, but ultimately settled on Kath, saying "bingo – 'that' was the voice.

"[40] Kath was one of the three primary lead singers of Chicago, with a vocal range between those of the other two, Peter Cetera's higher tenor and Robert Lamm's fuller, lower baritone.

He often collaborated with Cetera on lead vocals as they did in "Dialogue (Part I & II)," "Ain't It Blue," "In The Country," and "Brand New Love Affair".

[42] On Monday, January 23, after a party at the home of roadie and band technician Don Johnson, in Woodland Hills, Los Angeles, California, Kath began to play with his guns.

[47][48] The group's members were devastated over losing Kath and strongly considered disbanding, but were persuaded by Doc Severinsen, musical director of the Tonight Show band, to continue.

[50] At Chicago concerts, members Lee Loughnane (trumpet) and Robert Lamm (keyboards) have performed lead vocals originally sung by Kath.

[55] It made its United States premiere at the DOC NYC film festival in November 2016 under the same name,[56][57] and was soon after acquired by FilmRise, which planned a 2017 release.

[58] The film made its television premiere on AXS TV, under the name Chicago: The Terry Kath Experience, on November 7, 2017, and it was released as VOD and DVD on December 12.

[59] The film includes interviews with guitarists Jeff Lynne, Steve Lukather, Mike Campbell, Dean DeLeo and Joe Walsh, who all praised Kath's work.