"As soon as I hit it, I knew it was gone," Ramirez said. "So I was happy to move on."
Ramirez was slow reaching the milestone. He hit No. 496 on April 19 and had only three in 34 games before Saturday.
This one, however, was worth the wait.
"It was great, especially since I've been trying so hard the past three weeks just to get it done," he said. "It finally came and I'm happy. I'm proud of myself, of all the things I've accomplished. Now I can go and have fun."
As he got to first base, Ramirez exchanged a high-five with coach Luis Alicea. He slapped hands with third base coach DeMarlo Hale, then hugged on-deck hitter Mike Lowell as he crossed the plate.
Many of his teammates greeted him as he reached the dugout, where Ramirez received more hugs and bounced up and down in an embrace with David Ortiz and Julio Lugo.
The solo shot gave Boston a 5-3 lead. It traveled an estimated 410 feet.
"I'm happy, you know, about everything I accomplished in life," Ramirez said. "Not everybody has the chance to go and get to 500. I'm just proud to do it."
There were thousands of Red Sox backers at Camden Yards, and cameras flashed in the stands during every pitch to Boston's left fielder.
In his first at-bat, Ramirez hit a fly to the warning track in left field. He then grounded out to third and lined out to left before going deep in his fourth trip to the plate.
"I just wanted to get a good swing on the ball all day," Ramirez said. "And I did."
Orioles manager Dave Trembley said, "You could see he was aggressive up there. The worst thing we did was throw him a strike. It probably would have been better if threw the ball outside of the strike zone every time tonight because he seemed like he was in a hurry to get it over with."
Before each at-bat by the dreadlocked slugger, plate umpire Bob Davidson was given a special set of baseballs so there would be no confusion over which one was No. 500 if it landed in the seats.
The ball was caught by a Red Sox fan, Damon Woo, who presented Ramirez with the ball after the game. Ramirez said he will sell the ball and give the money to charity.
The drive enabled Ramirez to become only the seventh player in baseball history with 500 homers, 1,500 RBIs, 1,000 walks, 475 doubles and a .300 batting average. The others are Hank Aaron, Willie Mays, Mel Ott, Babe Ruth, Frank Thomas and Ted Williams.
"Obviously, he will go down as one of the greatest power hitters of all time," Trembley said of Ramirez.
Ramirez is the 12th-youngest player to hit 500 home runs; his 36th birthday was on Friday. The youngest was Alex Rodriguez, who did it eight days after his 32nd birthday.
It was Ramirez's 10th homer of the season and second of the week; he hit No. 499 on Tuesday in Seattle.
Before the game, Red Sox outfielder J.D. Drew asked Ramirez if his 500th homer would be an inside-the-park job.
"I know what you want to know," Ramirez replied. "You want to know when am I going to hit the 500? Don't worry about it. I hit it one day."
Ramirez knew it was only a matter of time before he reached the landmark, and made sure his pursuit was not a distraction.
"The one guy, out of all the 500 (home run) hitters it weighs on the least is probably Manny," Boston first baseman Sean Casey said. "He knows he's going to hit it. It's going to happen. But there's no pressure to make it happen."
Ramirez is the third player to reach 500 in a Red Sox uniform, joining Williams and Jimmy Foxx. Ramirez hit his first home run with Cleveland in 1993 and had 236 with the Indians before signing as a free agent with the Red Sox in December 2000. He has since hit 264 home runs with Boston.
It took him 2,004 games and 7,263 at-bats.
Ramirez is now four homers short of tying Eddie Murray for 23rd on the career list. Barry Bonds is baseball's career leader with 762.
It was Ramirez's 16th home run at Camden Yards but the first since May 15, 2006. His last four homers have been on the road.
Cincinnati slugger Ken Griffey Jr. hit his 599th homer earlier Saturday in the Reds' 8-7, 10-inning victory over the Atlanta Braves.
