Soon Les started listening to jazz bassists like Stanley Clarke and he quit Blind Illusion to explore other musical possibilities. He played in some Jazz and Funk bands and it was around this time that he first met Todd Huth. Eventually, Blind Illusion asked Les back and he rejoined for about a year. During this time, he met Larry LaLonde, before he quit again to Join the Tommy Crank Band. This was an R&B band full of older guys who played at Hell's Angels bars all over Northern California. Les spent three years playing four sets a night, three to five days a week with the Tommy Crank Band. Les cites this time (1981 or '82) as being very important in his musical growth, it was then that he learned to groove.

After his 21st birthday, Les left the Tommy Crank Band, "to become this big, famous guy." He started answering Ads in the paper for musicians, but nothing panned out. He rejoined and soon after quit the Tommy Crank Band to start his own band. In 1984, Claypool started Primate with guitarist Todd Huth and a drum machine. According to Les, "Primate only lasted about a month because there was another band called the Primates." The lawyer for this band called Les and told them to change the band's name, or else.

Primate/Primus' first drummer was Vince "Perm" Parker, an old friend of Les' who was in the high school jazz band. Les sold his car, a Cougar, in order to finance a demo, and then they gave it to everybody. The demo started to get some airtime on a local station, The Quake, but soon after, the station went under.

Primus' second drummer was Peter Libby, and then sometime in 1985-87, he was out of the picture and Les called up Jay Lane to find out if he knew of any drummers that might play play with them. At this time, Jay was playing with a band called The Freaky Executives, who were very popular around Berkeley. The Freaky Executives were being "dicked-around" by their record company, so Jay said that he would come and join Primus. Les was quite happy because Jay was his favorite drummer. This version of the band recorded another demo, entitled "Sausage", which led later to the band of the same name in '94.

In 1989, Jay Lane quit Primus, because the Freaky Executives got a big break. While they were auditioning for a new drummer, Todd quit because he felt that he was neglecting his family by being on the road all of the time. Les joined Blind Illusion for a third time, filling in for the normal bass player. He then convinced Larry "Ler" LaLonde (born September 12, 1968) to join Primus.

Brian "Brain" Mantia was Primus' fourth drummer, but he was only in for two weeks, and then he broke his foot skateboarding. Primus had a big show with Faith No More coming up, so they were forced to find another drummer. (Brain went on to be in The Limbomaniacs, Praxis, and MIRV.)

Primus' fifth drummer, Tim Wright was another short-lived member, and through auditioning, Les and Ler hired Tim "Herb" Alexander (born April 10, 1965) in October or November of 1989. A month later, they recorded Suck on this for free, thanks to Matt Winegar, using the same setup that was used to record the Sausage demo. Les borrowed $3,000 from his dad, and used it to get 1,000 records pressed. Then, Les and Ler drove all over to record stores, selling the album. They sent out 200 copies to radio stations all across the country, and were discovered for the first time by College radio stations. This brought many offers from record companies, Primus decided to sign with Caroline because they seemed to be the coolest, and they were willing to do just a one album deal. Primus didn't want to be tied down.

Caroline re-released Suck on this in a much larger scale, and Primus recorded Frizzle Fry for $11,000 using the profits from Suck on this.

Sometime in late 1990 or 1991, Interscope's A&R man, Tom Wheller came to a club to see Primus and he liked them and said that he wanted to sign them. Les was impressed that he didn't know that they had sold 80,000 copies of their albums, he just saw them and thought they were good. Les also liked the independent atmosphere of Interscope. Primus was the second act signed to Interscope, the first was Gerardo.

Primus' first release on Interscope was their 1991 album, Sailing the Seas of Cheese. It cost $30,000 to produce, and was rewarded by going gold. They supported this album by touring with Anthrax, Public Enemy, U2 and Rush.

In 1992, Primus released an EP featuring songs by Peter Gabriel, XTC, the Residents, the Meters and Pink Floyd, called Miscellaneous Debris.

Pork Soda was the title of Primus' 1993 effort. The album explored the darker side of the band and had an eerie feel throughout. Les has said that they were taking a lot of flak for not being serious about anything, plus the band had been touring almost nonstop for four years. Les explains, "The album reflects how we were all feeling at the time." They recorded Pork Soda in their rehearsal space, using recording equipment that was loaned to them by the Grateful Dead. Somehow, the album still cost $60,000.

Primus toured with Rush again in support of the album. And later, they headlined Lollapalooza '93, which featured Alice in Chains, Tool, Living Colour, Dinosaur Jr. and more. Then, finally, they headlined their own tour.

Also of note from 1993 was the launch of Les' own record label on Interscope, called Prawn Song. This label introduced such acts as MIRV, The Charlie Hunter Quartet, Laundry and Porch. When Les originally released Suck on this, it was on Prawn Song.

1994 was downtime for Primus. Les was joined by ex-Primus members, Jay Lane and Todd Huth to record the album The Riddles are Abound Tonight as Sausage. The album was a collection of songs that they had written together that otherwise wouldn't get heard. The other members worked on side projects as well. Larry worked on Beanpole, while Tim worked on Laundry.

In 1995, Primus returned and released Tales from the Punchbowl, an album that was several shades lighter than Pork Soda. Months later, they released a CD+ version of the album, that featured, among other stuff, visuals for every song on the album. Primus toured exaustively in support of this album, bringing along Mike Watt, Helmet, and the Meat Puppets.

After the Primus tours finished in 1996, Les recorded another side project entitled Les Claypool and the Holy Mackerel Presents Highball with the Devil. The album featured Les on basses, vocals, and on many songs, guitar and drums. The other musicians on the album were Jay Lane, Joe Gore, Mark "MIRV" Haggard, Charlie Hunter, Henry Rollins and the infamous Bob C. Cock. The tour featured Les, MIRV, Bob Cock and Brian "Brain" Mantia on drums.

Also in 1996, it was announced that Tim "Herb" Alexander was no longer a member of Primus. According to Les, the split was agreed upon from both sides with no hard feelings, he described it as a marriage that slowly decayed.

Herb is now playing again with Laundry, minus their singer, Toby Hawkins. Apparently, Herb does both drumming duties and vocals. They have been touring with MIRV and have an album due out in 1999. Not long after Les and Ler announced that Herb was out, they chose Brian "Brain" Mantia as the new drummer for Primus.

They spent the last half of '96 working Brain into the set and writing new material. Brain performed for the first time with them at the Primus Freak Out on December 31, 1996. Brain learned the Herb-drum parts almost note for note, minus the double bass drum.

On July 8, 1997, (June 24 - Vinyl) Primus released the Brown Album, which showcased a new, funkier, faster sounding Primus.

After a short European tour, Primus signed on to HORDEfest '97 along with Morphine, Ben Folds Five and Niel Young. Then, it was right back to the road for them on the Brown Album tour. The opening acts for the tour were Buck-o-Nine, Powerman 5000 and Limp Bizkit. Primus finished off 1997 with another New Year's Freak Out, two songs of which ended up on Rhinoplasty.

Primus started 1998 out by recording a new EP of covers, with some live tracks, titled Rhinoplasty, and by touring on Sno-Core with the Aquabats, Alkoholiks, Long Beach Dub All-Stars and Blink 182. In April, they toured Austrailia. And, in June and July, England.

In December, Primus released their second home video, titled Videoplasty. It is a collection of strange animation, behind-the-scenes footage, live footage taped at the Pheonix Theater in Petaluma, California, and music videos for Shake Hands with Beef, Over the Falls and The Devil went Down to Georgia. The 1998 New Year's Freak Out was split into two different nights. The First night featured MIRV and Laundry as opening acts and Spearhead opened on the second. The final song of the year was "1999" by the artist formerly known as Prince, and the vocals were handled by none other than Bob C. Cock.

Primus is now in the process of working on their next album.