He came to New York in 1976, first working with Machito and his Afro-Cuban orchestra, and then toured and recorded with Ray Barretto, Steve Kuhn, Lionel Hampton, Brother Jack McDuff, and Carla Bley.
[3] In the mid-1980s, global and especially Latin influences began to inflect Slagle's work, and he appeared on albums by Milton Nascimento and recorded Rio Highlife in Brazil.
Slagle recorded his composition “Hopewells Last” dedicated to his brother, Stuart, who succumbed to suicide in 2007, and subsequently arranged it for the VJO Big Band in Sweden.
[6] Since 2016, all of Slagle's records have been produced by Rick Simpson; Alto Manhattan (2017) Dedication (2018) Spirit Calls (2019) Alive In Harlem (2020) Nascentia, (2021) and Into The Heart Of It.
In 2011, Slagle published a composition and improvisation workbook for the creative musician, including stories about his life, in "Scenes, Songs and Solos" (Schaffner Press).