Anthony Rendon's solo home run and a two-run shot off the foul pole by Howie Kendrick helped the Nationals erase a 2-0 deficit and spoil a nearly flawless effort by Astros starter Zack Grienke. Juan Soto made it 4-2 Washington with a two-out RBI single in the eighth inning.
Pitcher Stephen Strasburg, who went 2-0 with a 2.51 ERA and 14 strikeouts in two starts, was named the Willie Mays Most Valuable Player of the Series.
The Series title capped a remarkable season for the Nationals, who finished 93-69 after a 19-31 start. Washington reached the postseason as a wild-card team, then defeated Milwaukee in a wild-card game, topped the Los Angeles Dodgers in the National League Divisional Series, then swept St. Louis in the best-of-seven National League Championship Series.
The Astros; who won the Fall Classic in 2017, owned the best record in baseball during the 2019 regular season (107-55) and had the best record at home (60-21) but lost all four games at Minute Maid Park to the Nationals.
It was the fifth time this decade the World Series was extended to a seventh game and the 40th time in MLB history. The Nationals' win made it the fourth straight time a road team took Game 7; road teams now own a 21-19 record in Game 7.
Yuli Gurriel put Houston ahead early, opening the second inning by hammering a Max Scherzer slider for a solo home run to left field.
The Astros made it 2-0 in the fifth inning on Carlos Correa's two-out RBI single down the third-base line.
Anthony Rendon cut the Nationals' deficit in half when his one-out homer off Zack Greinke in the seventh made it 2-1. Greinke was taken out of the game after walking Juan Soto, and Howie Kendrick greeted reliever Will Harris by clanging a two-run homer off the right-field foul pole to make it 3-2.
The last time Washington celebrated a World Series title was Oct. 10, 1924, when 31,667 fans at Griffith Stadium saw the Senators edge the New York Giants 4-3 in Game 7. That 12-inning contest in Washington took three hours to play and ended when Earl McNeely's bad-hop grounder skipped over the head of Giants third baseman Fred Lindstrom and allowed Muddy Ruel to score the winning run from second base.
The winning pitcher that day was Hall of Famer Walter Johnson, who pitched four innings in relief.
Washington started Scherzer in Game 7, while Houston countered with Greinke. According to MLB.com, it was the first time two previous winners of the Cy Young Award started Game 7 of the World Series.
That Scherzer was able to start Game 7 was an effort that can now be seen as legendary. He got a cortisone shot a few days ago to relieve pressure on a nerve that caused pain on his right arm, ESPN reported. After receiving treatment from the team's chiropractor, Scherzer threw in the outfield before Game 6 and even began warming up in the bullpen at one point during the game, the sports network reported.
The Nationals signed Scherzer to a $210 million contract four years ago, The Washington Post reported. Astros gave up four prospects to obtain Greinke at the trading deadline in July, the newspaper reported.