Matt Lauer, who was fired by NBC on Wednesday over a sexual harassment allegation, was one of the network’s most high-profile journalists and the face of one of its most valuable programs, “Today,” since the mid-1990s.

Mr. Lauer spent 21 years at “Today,” the longest tenure for the show, and was often at the center of rumored tension among other anchors on the program. In his role, he led NBC’s coverage during major news events, including on the morning of Sept. 11, 2001, and engaged in memorable interviews, such as his combative questioning of Tom Cruise in 2005.

In 1997, he replaced Bryant Gumbel.

After several years as the news reader on “Today,” Mr. Lauer replaced Bryant Gumbel as the co-anchor on Jan. 6, 1997. His first week was full of jitters and awkwardness, but those five days were the second-best-rated week in the show’s history at the time.