During his time as President of NBC Entertainment (1991–1998), Littlefield oversaw the creation of many shows for the network throughout the 1990s such as The Fresh Prince of Bel-Air, Wings, Blossom, Mad About You, Sisters, Frasier, Friends, ER, Homicide: Life on the Street, Caroline in the City, NewsRadio, 3rd Rock from the Sun, Suddenly Susan, Just Shoot Me!, Will & Grace and The West Wing.

[citation needed] In 2012, he wrote a book, with T. R. Pearson, about his time at NBC entitled Top of the Rock: Inside the Rise and Fall of Must See TV.

[4][5] Since leaving NBC, Littlefield has executive produced TV series such as My Generation, Fargo, The Handmaid's Tale, and The Old Man.

[7] Littlefield had a brief cameo as himself in a 1997 episode of The Larry Sanders Show and again appeared as himself in the 1999 film Love Stinks.

[10] Balaban had previously played Russell Dalrymple, a character based on Littlefield, during the fourth season of Seinfeld.