His research focus is signal processing and machine learning techniques, which he applies to speech recognition and music analysis. He received his PhD in electrical engineering at MIT. Upon completion of his degree, he worked at ICSI as a postdoctoral researcher from 1996-1999, then as a staff research scientist before being offered his current position at Columbia in 2000. Ellis continues to maintain an active affiliation with ICSI. Since leaving ICSI, he has worked with ICSI's Speech Group on the EARS project as well as on speech processing for meetings, and he is involved in this issue's featured project, GALE.