Ususally when a major recording artist releases something uncharacterstic or just plain weird, such as Lou Reed’s Metal Machine Music, Neil Young’s Trans (or Everybody’s Rockin’) or Elvis Costello’s Almost Blue, not are they only commercially unsucessful, but also much less popular than the artists typical releases. Are there any notable exceptions?
Well, Pink completely shifted from R&B with “Can’t Take Me Home” to pop/rock with “M!sundastood”, and the latter sold very well (anyone remember “Get The Party Started”?). Although I don’t know if you can call it “uncharacteristic”, since she had only released one other album and it wasn’t written by her.
**Peter Gabriel III **probably qualifies (the one with the melting face of the artist himself), but actually helped to kick him to eventual superstardom. The cuts on it were described in one review as “stark and obsessive”, but it had the relatively catchy “Games Without Frontiers” single, which helped sell the album.
It might not have been to everyone’s taste, but Sting’s “Songs from the Labyrinth” charted unusually high on the pop charts for a classical album. Which reminds me, David Bowie’s contributions to the Labyrinth movie soundtrack made for a fun and successful musical diversion (especially when compared to Tin Machine).
Paul Simon’s Graceland was different from anything he’d done before, and there’s no question it was a success.
Too early to be really relevant - but Ted Weems led a big band for 30 years with only one hit record, Heartaches. Not only was it a rumba by a band that never played Latin music, it was also one of his very few instrumentals.
That’s probably one of the best examples right there- not only uncharacteristic of the artist but also music not commonly poplular (in the US anyway), period.
I’m not sure how different Graceland is from his previous albums. Despite the African influences, it still has a very Simon-y feel to it, and when I play, say, his eponymous album with this back-to-back, it doesn’t seem like such a big change.
For the OP, would “Hey Ya” on Outkast’s 2003 album count? That rock song from the rap group is definitely one of their top 5 in popularity.
Andrew Lloyd Webber wrote two very successful and very good classic pieces: “Variations” for his brother Julian and “Requiem” for then-wife Sarah Brightman.
If we are going to talk Paul Simon, the the successor to Graceland, Rythm of the Saints was probably a bigger change musically and as I recall, sold poorly.
In hindsight it seems like a perfectly normal progression, but if you asked this question in, say, 1966, when the Beatles released Revolver, that would fit the bill nicely. From “A Hard Day’s Night” to “Tomorrow Never Knows” in two short years…and with obviously continued success…wow!
Does that include changing your “stage persona”? If yes, David Johansen gained infamy via the rock group The New York Dolls who then in the late '80s became Buster Poindexter, “performing a mixture of jazz, lounge, calypso” [wikipedia].
Tim Fite released “Over the Counter Culture”, which is an alternative hip-hop album. All his other albums are more acoustic, Folk, alt-country kind of stuff. I don’t know if I would consider it a success since most people haven’t heard of him though.
“Over the Counter Culture” is a great album by the way, and you can download it for FREE at his website. The album is all about consumerism, so he felt that it would be hypocritical to charge for it. pretty cool
Bob Dylan. Damn near every album he has ever released is different from the last, yet good and successful. To narrow it down to three:
Bringing it All Back Home (aucostic Dylan goes electric)
Nashville Skyline (rocking Dylan goes country
Slow Train Coming (Jewish Dylan goes Christian)
Bruce Springsteen’s recent Seeger Sessions album has been a huge success (here at least). It’s not really much like most of his other albums, the set comprising of country/folk standards.
David Johansen on “David Joansen and the Harry Smiths” - not sure how successful, but they did a followup so probably it was somewhat successful anyway.
Not sure if Elton John’s Tumbleweed Connection would count, but I’ll throw it out for discussion anyway.
If you had to sum it up in one sentence, you could describe it as “Elton John tries country music.” And to a large degree, it is country music–maybe not Hank Williams, but it certainly wouldn’t necessarily be out of place among the “new country” of the early 1990s.
But there’s the problem. Tumbleweed wasn’t released in the early 1990s; it was released in 1970. Elton John wasn’t very well-known then, and he hadn’t fully settled into his career as a writer/performer of pop standards at that point. The album was successful, reaching No. 2 on the UK album charts and No. 5 on Billboard in its best performance, and No. 463 on Rolling Stone’s 500 Greatest Albums of All Time (cite), but because this country album by (as the future would prove) non-country artist Elton John came so early in his career, it’s hard to know if it’s among the albums that the OP is looking for.
Maybe this is debatable, but Frank Zappa’s Hot Rats comes to mind. There were other departures before it (Lumpy Gravy, or Cruisin’ with Ruben and the Jets, for instance), but they didn’t qualify as being popular even by FZ’s standards.
Mike Keneally’s Wooden Smoke is another, for the three of us on this board who like his work. 
I think the Alice in Chains album Jar of Flies is a pretty good example. The album is barely over 30 minutes long and only has seven songs but was the first EP ever to reach #1 on the Billboard US album. The single “No Excuses” is the only Alice in Chains Top 40 hit and their only song to hit #1 on the mainstream tracks chart.
Back in the 70’s, Van Morrison would completely reinvent his style album to album - acoustic folk jazz for Astral Weeks, Horn based soul for Moondance, New Orleans for Band and Street Choir, Country for Tupelo Honey, Big Band Soul for St Domonics Preview, Jazz for *Hard Nose The Highway * then back to Astral Weeksy-ness for *Veedon Fleece * then funk for Period of Transition, then pop for Wavelength…