Nia Long has worked non-stop in film and television since first appearing in John Singleton's seminal drama Boyz N the Hood. Her many and varied feature credits include Made in America, Friday, Love Jones, Hav Plenty, Soul Food, In Too Deep, The Best Man, Stigmata, Held Up, The Broken Hearts Club, Boiler Room, and the first Big Momma's House, for which she earned nominations for both an NAACP Image Award (Outstanding Actress in a Motion Picture) and a Blockbuster Award (Favorite Actress). More recently, Long has been seen in such movies as Baadasssss!, Alfie, and Are We There Yet?

On television, the actress starred as Officer Sasha Monroe on the NBC drama Third Watch, for which she won NAACP Image awards in both 2004 and 2005 for Outstanding Actress in a Drama Series.

Long was also a regular on the daytime drama The Guiding Light, had recurring roles on such series as The Fresh Prince of Bel-Air, Moesha, and Judging Amy, and was seen in the telefilms If These Walls Could Talk 2 and Sightings: Heartland Ghost.