https://www.nytimes.com/2005/12/24/arts/desig...

Old Business, New Name: Behold the Gallerist

Dec. 24, 2005

A fashionable new word is bubbling up in the New York art scene: gallerist, as a substitute for art dealer. Not, of course, just any art dealer. A gallerist is directly involved with the care and feeding of artists, rather than with the quick turnover of art objects.

[..]

Barbara Gladstone, a gallery owner of long standing who likes the word, said: "A dealer is someone who buys and sells paintings, but doesn't deal with artists. Gallerists represent artists. It's a completely different activity."

Searching American newspapers for "gallerist", I find plenty of articles that use it, implying that the word has taken root.

gallerist, n.

................

2. A person who owns or runs an art gallery; (in later use also) a person who exhibits and promotes artists' work in galleries or other premises, in order to attract potential buyers.

[OED]

(OED's first specimen sentence in this sense dates to 1966.)