Citing host George H.W. Bush's vision for public service as the launch pad toward that goal, Obama spoke for just under 20 minutes and described the 41st president as "an inspiration to us all."
Secretary of Defense Bob Gates, former president at A&M, joined Bush on stage in welcoming Obama to Aggieland.
Meanwhile, just under 1,000 protesters were about a block away from the event at Rudder Tower, though Obama never saw them, officials said.
Bush invited Obama to speak about the importance of public service and volunteering, issues discussed as a part of the daylong tribute sponsored by the Points of Light Institute.
"We've been doing everything we can to get involved," Obama told the 2,500 invited guests, advising those younger in the crowd to not stand by and watch those struggling in their communities. "In the end, service binds us to each other and to our community and to our country in a way that nothing else can."
Bush was the first president to create a White House department responsible for promoting volunteerism.
Across campus earlier in the day, Bush and wife Barbara briefly dropped in at a roundtable discussion at the Bush Conference Center, where Points of Light CEO Michelle Nunn discussed the strides made since the institute opened under his guidance 20 years ago.
“The service movement has matured and is now working together to create change,” she said to the crowd of about 100 or so. “One of the pieces of the momentum has been the growth of collaboration.”
Bush told the crowd that he hoped they later would give Obama an “Aggie welcome.”
By mid-afternoon, the protesters poured out of Spence Park and lined Houston Street, which dead-ends at Rudder Tower. Many chanted, "Hands off Texas," at hundreds of people heading toward the auditorium, while a much smaller gathering cheered them on.
Colleen Fisher, a senior biomedical science major from Parker Heights, was critical of the protesters — a group that was expected to swell to more than 1,000 — saying Obama’s purpose on campus was to put the spotlight on the importance of community service, not to talk about his agenda.
“It’s exciting to have the president here, but it’d be better if you could hear or see him,” Fisher said.
Bryan resident Dana Alexander, who works at the nearby A&M Career Center, took time off her job to show her support for the president by holding up two signs: One congratulating Obama on winning the Nobel Peace Prize and the other stating “Healthcare for All Americans.”
“I wanted to show him that Texas has a little bit of blue in it,” Alexander said. “I love what Obama stands for. He’s a positive man.”
Earlier this week, Bush sent out a statement reminding anyone who might not know why he asked Obama to make his first-ever visit to College Station. Bush said it had nothing to do with politics.
Paul Reiger, chairman of the Brazos County Republican Party who stood among the protesters Friday morning, said he respectfully disagreed with Bush.
“That’s like going outside and saying it’s not about the weather — if you’re the president of the United States, it’s always about politics,” he said.
Reiger’s group, along with the College Republicans, made it clear that they weren’t associated with the “tea party” protesters — a conservative activist group that brought in hundreds from around the state. Most of the protesters were not students.
Alan Davis — who made the almost 100-mile trip to College Station this morning with almost 20 others from the Austin “tea party,” said he left the Republican Party after it nominated John McCain as a presidential candidate. He ended up voting for the GOP ticket, but said he was pushing for Sarah Palin and “secretly hoping that McCain would be sworn in and then have a heart attack and die.”
Davis was the first protester to show up at about 7 a.m. at Spence Park, not far from Rudder Auditorium where Obama is expected to speak this afternoon.
“I’m just a pissed-off senior,” the 67-year-old said. “I’m here because the tyranny of the federal government — bailouts, spending, inflation,” Davis said. “This government is into fascism. It’s gone away from socialism and into fascism.”
An estimated 40 members of the media requested credentials; an unknown number of the White House Press Corps also are in town.
Authorities blocked off the area around Rudder Tower at about 12:30 p.m., allowing only those with credentials inside.
• Eagle staff writers Matthew Watkins, Vimal Patel, Michelle Casady and Cassie Smith contributed to this report.