He debuted as a solo artist in 1989, and is known for his work conducting the Metropole Orkest and WDR Big Band Köln, as well as arranging music for musicians such as John Scofield, Joni Mitchell, Michael Brecker and Björk.

[3] His compositions can be heard on recordings by Gary Burton, Pat Metheny, Sean Jones, Michael Brecker, John Abercrombie and Charlie Haden.

His arrangements are also heard on recordings by Gregory Porter, Chaka Khan, Elvis Costello, Robbie Williams, Robert Glasper, Bobby McFerrin, Sting, as well as Herbie Hancock and Al Jarreau.

He has worked as an arranger, conductor, and/or producer on six Grammy Award-winning albums: Travelogue and Both Sides Now by Joni Mitchell;[9] Some Skunk Funk by Randy Brecker and Michael Brecker;[10] Brown Street by Joe Zawinul;[11] 54 by the Metropole Orkest and John Scofield;[12] and his own collaborative album with the Metropole Orkest, El Viento: The Garcia Lorca Project.

Another track from that album, "To The Edge of Longing", featured soprano Julia Bullock[12] and garnered Mendoza the Grammy Award for Best Arrangement, Instrumental and Vocals.