He is noted for "discovering" popular musical acts such as Hanson, Baha Men, Jonas Brothers, Joss Stone and AJR.

Greenberg also won a 2019 Grammy Award in the "Best Album Notes" category for his essay featured in the Stax '68: A Memphis Story boxed set.

Prior to founding S-Curve Records, he was Head of Artists & Repertoire for Mercury Records, where he served as executive producer of Hanson's single "Mmmbop", which spent three weeks at number one on the Billboard Hot 100 chart, and their debut album Middle of Nowhere.

S-Curve's roster/catalog includes Duran Duran, Andy Grammer, Hamilton star Leslie Odom Jr., 2018 Eurovision winner Netta Barzilai, reggae artist Conkarah, Tinted Windows, Fountains of Wayne, Nikki Jean, We The Kings, Joss Stone, A-WA, Betty Wright, Little Jackie, Tom Jones, Daisy the Great, Care Bears On Fire, Bruce Melodie, Yola, David Broza, Rachel Crow, Broadway star Joshua Henry, A Great Big World, Maxi Priest and Diane Birch.

That year, he also began managing the band AJR, with their debut single "I'm Ready" becoming certified Platinum in the U.S. and Australia.

He has co-written songs for Joss Stone, Jonas Brothers, Boyzone, Baha Men, The O'Jays, Leslie Odom, Jr. and others.

In 2020, Greenberg launched the pop music history podcast "Speed of Sound," produced by iHeart Media.