To source this, look at any HS level textbook, but if you need more in depth proof, you'll find it in Mark Seymour-Smith's biography of the guy, Thomas Hardy wrote a large number of highly regarded novels. The extremely nasty reaction to the last of those, "Jude the obscure", caused him to give up writing novels entirely. He did, however, continue to write poetry, and his poetry, too, is highly regarded.

Lest you think poetry and novel writing are too closely related to count, there are actually very few, if any, poets whose novels are highly regarded and vice-versa.

But I'll admit this isn't a very spectacular example. If you want better ones, maybe look into Michaelangelo (painter, sculptor, architect) or into people who combined succesful artistic careers with succesful non-artistic careers, like Da Vinci (of course) or Rubens (who ran a tremendously succesful painring studio in addition to being a highly sought after diplomat)

For true polymathy, however, I suspect you'll need to study Chinese scholars. The 11th century poet Su Dong Po, for example, is highly regarded as a poet but also as an administrator (he oversaw the building of waterworks along the West Lake) and even as a gourmet: tradition holds it he invented the dish named after him, the truly spectacular Dong Po pork.