Megadeth Forms And Releases Killing Is My Business...And Business Is Good

Fueled by the desire for revenge,Mustaine elevated the intensity of Megadeth's music, speeding up existing songs such as "The Mechanix", which Metallica's new line-up adapted into the much slower paced "The Four Horsemen". After unsuccessfully searching for a vocalist for nearly six months, Mustaine decided to handle lead vocal duties himself, while also serving as the band's primary lyricist, main songwriter, and co-lead and rhythm guitarist.

Early in 1984 Megadeth recorded a three song demo, featuring Mustaine, Ellefson, and Rausch, which contained early versions of "Last Rites/Loved to Death", "Skull Beneath the Skin", and "Mechanix". Kerry King (of Slayer fame), covered a handful of live dates while a permanent replacement was sought. After just a few shows in 1984, Lee Rausch was replaced by fusion drummer Gar Samuelson.On the strength of their three song demo, Megadeth signed with the New York based independent label Combat Records, and in December added second guitarist Chris Poland, a friend of Gar's from the fusion scene.

Early in 1985, the band was given $8,000 by Combat Records to record and produce their debut album. However, after spending half of the album's budget on drugs, alcohol, and food the band was forced to fire their original producer and produce the album themselves. Despite the resulting poor production, Killing Is My Business... and Business Is Good!, released in May 1985, was a well-received effort that blended elements of thrash, and speed metal.

The album features the first of many cover songs performed by Megadeth; a speed metal version of Nancy Sinatra's classic "These Boots Are Made For Walking" with lyrics altered by Mustaine. The song sparked controversy in later years when the song's original author, Lee Hazlewood, deemed Mustaine's changes to be "vile and offensive",and demanded that the song be removed from the album. Under threat of legal action, the song was removed from all pressings released after 1995. In 2002, however, the album was re-released with a partial version of the song, though with the altered lyrics censored by a "beep". In the Killing Is My Business... deluxe edition liner notes, Mustaine is strongly critical of Hazlewood, and notes he received royalties for almost 10 years before objecting to the altered version.

In the summer of 1985, the group toured the United States and Canada for the first time, supporting Killing Is My Business... with Exciter. During the tour, new guitarist Chris Poland abruptly left the band, and was replaced by touring guitarist Mike Albert.Poland later rejoined Megadeth in October 1985 however, shortly before they began work on their second album with Combat Records.