Characterized as something of an easy listening version of Howard Cosell--a comparably thoughtful but genuinely controversial sportscaster cum commentator of an earlier era--Costas expanded his NBC broadcasting duties after leaving "Later" offering high-profile interviews to NBC News programs including "Now" and "Dateline". He proved one of the more memorable, articulate and poignant on-screen contributors to documentarian Ken Burns' monumental "Baseball". Costas had gained so much respect that conservative journalist--and part-time sports nut--George Will even seriously proposed the much honored sportscaster as the next commissioner of baseball.

Costas started his broadcasting career at the Syracuse University (NY) stations WSYR- TV and Radio. He graduated to KMOX-AM radio in St. Louis, MO where he worked as the play-by-play voice of the ABA (basketball) Spirits of St. Louis. This led to regional broadcasts for local NFL (football) and NBA (basketball) telecasts for CBS Sports until 1980. Costas moved on to NBC Sports, initially as a sportscaster for pro baseball and college basketball. Gaining notice for his work with baseball analyst Tony Kubek on the "Game of the Week", Costas was the network's first-string baseball announcer from 1983-89. He hosted World Series pre-games in 1982, 1984, 1986 and 1988, announced the American League Championship Series in 1983, 1985, 1987 and 1989 and hosted the All-Star Game pre-game shows in 1983, 1985, 1987 and 1989. Costas' notoriety spread as he hosted the late-night portion of the 1988 Summer Olympics in Seoul, Korea. His laid-back manner proved soothing in the wee hours; this showcase probably helped him gain his own late-night talk show. During and after the run of "Later", Costas hosted, provided commentary, or merely provided guest appearances on a wide assortment of TV specials including "Diamonds on the Silver Screen" (AMC, 1992), "Bob Hope: The First 90 Years" and "Last Call! A Cheers' Celebration" (both NBC, 1993), "One on One: Classic Television Interviews" (CBS, 1993), "TV Guide's 40th Anniversary" (1998), "100 Years of Hope and Humor" (NBC, 2003). He also hosted his own nationally syndicated weekly talk radio show, "Costas Coast to Coast", from 1988-94. Costas subsequently served as one of three regular hosts in the program's revised format.

Costas was tapped by the cable news network MSNBC as part of the rotating host roster for "Internight" (1996-2000), a nightly talk program featuring conversations with newsmakers from politics, entertainment, sports and everyday life. He next landed at HBO as the central figure behind the interview series "On the Record with Bob Costas" (2001, 2002 special edition), a weekly sports talk/magazine series that focuses on topical sports issues and personalities from the playing field, front office and entertainment world. After he served as the primary host of NBC's coverage of the XIX Winter Olympics in 2002, his next HBO show was the one-hour sports magazine "Costas Now" (2005 - ). In 2005, the broadcaster was also named as the regular substitute host for Larry King on King's eponymous CNN talk show, conducting about 20 interviews a year in King's stead.

His celebrity status was further authenticated by several feature film cameos as himself in "The Paper" and "The Scout" (both 1994), "Open Season" (1995), "BASEketball" (1998), "Pootie Tang" (2001) and "Coach Carter" (2005). On TV he played of himself on a memorable 1996 episode of the sit-com "NewsRadio," a 1998 episode of "The Larry Sanders Show" and a 1999 episode of "The Drew Carey Show" along with several appearances on Robert Wuhl's sports agent sit-com "Aril$$" (HBO, 1996-2002).