In the 7 books he’s mentioned as the author of Fantastic Beasts.
During the series itself, Newt is only ever mentioned once, as the author of Fantastic Beasts and Where to Find Them, one of the required textbooks. During the series, he’s not said to have interacted with anyone else we know (like Dumbledore) and from how we hear about him, it’s not even clear he’s alive or lived during recent enough times where it would have been possible for him to have done this. For example, Great Expectations may be on a booklist, but that doesn’t mean anyone at the school personally knew or ever spoke to Charles Dickens. Newt’s name is on the course list as an author, but it’s not even clear if Fantastic Beasts and Where to Find Them is a modernly-written book, or if it was written ages ago by a long-dead wizard.
“Set Books
All students should have a copy of each of the following:
The Standard Book of Spells (Grade 1) by Miranda Goshawk
A History of Magic by Bathilda Bagshot
Magical Theory by Adalbert Waffling
A Beginner’s Guide to Transfiguration by Emeric Switch
One Thousand Magical Herbs and Fungi by Phyllida Spore
Magical Drafts and Potions by Arsenius Jigger
Fantastic Beasts and Where to Find Them by Newt Scamander
The Dark Forces: A Guide to Self-Protection by Quentin Trimble”
- Harry Potter and the Philosopher's Stone, Chapter 5 (Diagon Alley)
Fantastic Beasts and Where to Find Them, the book Newt wrote, is only ever mentioned twice in the series after it appears on the booklist, but Newt himself isn’t mentioned again in any way during the seven books. Fantastic Beasts is mentioned when Harry pretends he forgot it to go see Hagrid.
“At last, Harry had managed it by pretending he’d lost his copy of Fantastic Beasts and Where to Find Them, and doubling back after class one day.”
- Harry Potter and the Order of the Phoenix, Chapter 27 (The Centaur and the Sneak)
It’s mentioned again when Hermione explains how she recognized the Erumpent horn.
“There’s a description in Fantastic Beasts and Where to Find Them! Mr Lovegood, you need to get rid of it straight away, don’t you know it can explode at the slightest touch?”
- Harry Potter and the Deathly Hallows, Chapter 20 (Xenophilius Lovegood)
Those are the only mentions of Newt Scamander or his work during the seven books.
The Fantastic Beasts textbook showed he spoke to Dumbledore.
Though the seven books don’t show or reference Newt interacting with the characters we know, in the Fantastic Beasts and Where to Find Them textbook, Albus Dumbledore mentions in his foreword that he was honored when Newt asked him to write it. So yes, Dumbledore does mention Newt, though not in a way that implies they had known each other before his writing the foreword.
“I WAS DEEPLY HONOURED when Newt Scamander asked me to write the foreword for this very special edition of Fantastic Beasts and Where to Find Them.”
- Fantastic Beasts and Where to Find Them
This means Newt Scamander would have had to speak to Dumbledore at least once. It’s not mentioned that they knew each other well, but it is mentioned that they spoke at least once. Dumbledore also doesn’t say he taught Newt, so nothing written there even hints at them knowing each other in any way other than Dumbledore knowing that Newt wrote a very good textbook.