Mr. Bush emerged from the dugout in a red home-team jacket to mostly cheers, Mr. some boos and lots of camera flashes. Waving to the crowd, he walked straight to the mound and promptly launched a high ball toward home plate. Nationals catcher Brian Schneider reached up and snatched the ball cleanly, sparking more cheers.
Joe Grzenda, the last pitcher in the Washington Senators' final home game in 1971, provided the ball he had used in that final game.
The president walked back across the diamond to another round of cheers from fans packed into 46,000-seat RFK Stadium. He waved and smiled before disappearing into the dugout.
Mr. Bush watched the game from a box behind home plate with baseball commissioner Bud Selig, first lady Laura Bush, daughter Jenna and others.
Under a blue sky and mild temperatures, Mr. Bush executed the ceremonial first toss with the skill of a guy who knows baseball. He was a part-owner of the Texas Rangers before running for governor of Texas.
Mr. Bush practiced his wind-up in recent days, said White House spokesman Scott McClellan, before traveling to Rome last week and most recently on Wednesday.
Earlier in the day, Bush told newspaper editors meeting in Washington: "I've got a decision to make today. Do I go with a fast ball or a slider?"
Mr. Bush's pitch came 95 years to the day that President William Howard Taft did the same at a game between the Senators and Athletics, the beginning of a tradition.
The Senators left for Texas in 1972, but baseball returned to the nation's capital with the home opener against the Arizona Diamondbacks.
From the chants of "Lets go, Nats!" at a VIP luncheon to the excitement in the eyes of returning old-timers, Washington, D.C., ushered in the new era of baseball with an all-day party.
In a city that went 12,250 days — since 1971 — without hosting a regular season big-league game, Thursday night's Washington Nationals' home opener against the Arizona Diamondbacks was a joyous exclamation point for celebrations that began 6½ months ago with the announcement that the Montreal Expos were heading south.