Bonds, who remains at the epicenter of an enduring controversy about whether he used steroids, put himself on a different plateau in the hierarchy of sluggers when he swung on a 3-and-2 pitch from Byung-Hyun Kim of the Colorado Rockies. He sent the ball soaring over the fence just to the right of straightaway center field, an estimated 445 feet from home plate.
Babe Ruth and moved the 41-year-old slugger into second place on baseball's all-time home run list, 40 behind Hank Aaron's record total of 755.
"It can't get any better than this," Bonds said later, wearing a black T-shirt with 715 in orange numbers on the front. He said his teammates toasted him with champagne in the clubhouse.
"I've made everyone wait longer than I have in the past, but there's no greater place for it to happen than San Francisco."
Bonds paid tribute to Ruth and also said it's possible to catch Aaron, given enough time.
"It's a great honor, it's an unbelievable honor, but Hank Aaron is the home run king," he said. "I have a lot of respect for Babe Ruth and what he did for baseball, but Hank Aaron is the home run king."
The span between Bonds' first home run and his 715th covered 19 years 358 days.
His son, Nikolai, the Giants' batboy, jumped on home plate as he waited for his father. They hugged, then the celebration began.
A sellout crowd of 42,935 at AT&T Park coaxed Bonds to come out of the dugout twice to acknowledge their cheers and standing ovations. He saluted the fans with his batting helmet.
Two banners, one picturing Bonds and the other Aaron, were unfurled from the light towers in center field. A smaller one, which showed the number 715 trailing a baseball framed by two towers of the Golden Gate Bridge, was draped over the wall in left field, next to a permanent banner that featured likenesses of Bonds, Aaron, Ruth and Willie Mays.
Orange and black streamers were shot into the sky and the scoreboard displayed only three numerals: 715.
Home runs may be his signature, but lately they have been hard to come by for Bonds, who had 24 plate appearances between Nos. 714 and 715. He was stuck on 714 for eight days, since May 20, when he homered against left-hander Brad Halsey of the Athletics at Oakland. His 713th was May 7 at Philadelphia.
The home run chase has been far from carefree for Bonds, whose achievements have been under scrutiny since his appearance in 2003 before a federal grand jury at which he reportedly denied knowingly using steroids. Federal prosecutors have indicated they are looking into whether Bonds committed perjury during his testimony.
"Steroids, no steroids, who knows who's taking them?" Kim said. "They don't hit the home runs. He's a good hitter."
Climbing rung by rung up baseball's home run ladder was a daunting task, and comparisons are not easy to come by, but scaling Mt. Everest is easier. More than 90 have made it to the summit of the world's highest peak in the last month alone.
Hours before the first pitch, Giants Manager Felipe Alou had a bemused expression as reporters performed their daily ritual, crowding into his office to talk about Bonds. Alou said he thought a home run by Bonds would change the clubhouse atmosphere once again.
"The feeling here is not the one before 714," he said. "The atmosphere was kind of heavy. Now it doesn't feel like that, but it's there. It's just something to do.
"The average customer wants to see 715, we want to see more than that, like two or three a game. I don't believe 717, 719, 728, whatever, is going to be that important."
After the game, Alou said he was pleased for Bonds, and for the Giants.
"We're glad it's over," he said.
As it turns out, 715 had a lot going for it, right at the intersection of baseball history and numerology. Ruth smacked his 126th home run on June 14, 1921, to tie Sam Thompson for the most home runs in the major leagues. So Bonds' 715th homer ended a stretch of 84 years and 348 days that Ruth had been first or second on the all-time list.
Ruth had been in second place since Aaron hit his 715th, April 8, 1974.
Kim is the 421st pitcher to give up a home run to Bonds, who has shown a keen sense of geography about hitting homers.
Many of his more significant home runs have been hit at the ballpark in China Basin, currently known as AT&T Park, including his 500th, his 600th, his 660th to tie Mays and also his 700th. In 2001 Bonds hit his 73rd home run, the single-season record, at the stadium, then called Pac Bell Park; it came on the final day of the season, against Dennis Springer of the Dodgers.
The baseball that Bonds hit for his 715th landed on an elevated platform beyond the fence, where it stayed for several minutes before rolling off.
It was retrieved by Andrew Morbitzer, 38, of San Francisco, a marketing director for a software company. He was standing in line at a concession stand under the bleachers and looked up to see the baseball falling toward him. He said he caught it with one hand.
Morbitzer, a Giants fan, said it was his first game this year. He has not decided what to do with the baseball.
"I get to be a small part of a big day," Morbitzer said.