In his senior season, he served as a captain of Duke's 1988 Final Four team and was named NABC National Defensive Player of The Year.

He joined the professional ranks after spending four seasons as an assistant at Illinois State University under head coach Bob Bender.

King also spent one year as a color analyst for ESPN's men's basketball coverage of the Ohio Valley Conference.

As general manager of the Nets, King's legacy in the NBA was hurt by a series of oft-criticized trades that were deemed among the "worst in league history", notably trading multiple unprotected first-round picks to the Boston Celtics (two of which would later become All-Stars Jaylen Brown and Jayson Tatum) in exchange for older star-quality players in Kevin Garnett and Paul Pierce alongside Jason Terry.

[citation needed] On March 28, 2022, Billy King was hired by Modern Executive Solutions as a Senior Partner Head of Sports and Entertainment.