The honors -- voted on annually by the Baseball Writers' Association of America -- were announced Monday on MLB Network. Lewis and Williams are the first pair of Black baseball players to sweep the top rookie accolades since 1984, when Dwight Gooden and Alvin Davis did it.
"I feel like you need someone who looks like you to show you it's possible," Williams told MLB Network. "Growing up, I had guys like Derek Jeter and other biracial and Black players who just kind of opened the door to that possibility for me.
"When you don't see anyone who looks like you, it doesn't feel like it's attainable, in a way."
Williams, 26, also is the first relief pitcher to win the award in either league since 2011. The right-handed pitcher went 4-1 with an 0.33 ERA in 22 games last season for Milwaukee. He allowed just eight hits and one run in 27 innings.
Williams edged Alec Bohm of the Philadelphia Phillies and Jake Cronenworth of the San Diego Padres to win National League honors. The Brewers pitcher also won the 2020 National League Reliever of the Year Award.
"It shows how good of a bullpen we have if I can win both of these awards and I'm not even good enough to be our closer," Williams said.
Williams was a second-round pick by the Brewers in the 2013 MLB Draft. The Hazelwood West High School (Hazelwood, Mo.) product made his MLB debut Aug. 7, 2019, but retained rookie eligibility.
Lewis was the No. 11 overall pick by the Mariners in the 2016 MLB Draft. The Mercer University product made his MLB debut Sept. 10, 2019.
American League and National League MVP Award winners will be announced Thursday on MLB Network.