Sarah Thomas made her NFL regular-season debut on Sunday as part of the referee crew for the Kansas City Chiefs and the Houston Texans game in Houston.
Thomas was the line judge. The 42-year-old mother of three, a Mississippi resident, has been a football referee since working high school games in 1999.
The NFL officially hired Thomas as the league's first full-time female official in a groundbreaking announcement in April.
Thomas, who became the first female to officiate an NCAA football game in 2007, has previously been a finalist for an NFL job.
The Chiefs beat the Texans, 27-20, in the teams' season opener.