Harlan's broadcasting career began in 1982, when he became the TV and radio voice of the NBA's Kansas City Kings (now the Sacramento Kings). He then was a basketball announcer for his alma mater, the University of Kansas, for one year, then went on to call games for the NFL's Kansas City Chiefs from 1985–93. Harlan also split time with the University of Missouri (1986–89) calling football and basketball games, and worked as the play-by-play voice of the NBA's Minnesota Timberwolves for nine seasons (1989–98). On the network level, Harlan called NFL football for NBC in 1991, college football for ESPN in 1992–93, NFL for Fox from 1994–97, and joined Turner Sports in 1996 to cover NBA playoff games (he would begin calling games throughout the entire season in 1997, which he continues to do to this day). He began working for CBS in 1998.
In addition, Harlan has called Jacksonville Jaguars, Chicago Bears and Green Bay Packers preseason games; basketball games during the now-defunct Goodwill Games, which were owned by Time Warner; college sports on ESPN; and several bowl games during college football seasons. A Wisconsin native, Harlan attended the University of Kansas and graduated in 1982 with a broadcast journalism degree. He took sportscasting classes under the guidance of former Super Bowl and Chiefs play-by-play voice Tom Hedrick.
He has also lent his voice on the NBA 2K video game series. Curiously, his voice is similar to fellow NBA on TNT announcer Marv Albert that 2K Sports turned to him as a play-by-play announcer for said video game, in response to Albert being the voice on competitor EA Sports' NBA Live series.