WATERVILLE, Maine — Former British Prime Minister Tony Blair urged Colby College seniors at Sunday’s commencement ceremony to never stop learning and to always have humility.

“The greatest people I’ve met in my life have been humble,” he said. “Successful people are not defined by a restless search for fame or fortune, but by an insatiable desire to be better … don’t be afraid to fail. We all do. Be afraid of not trying; that’s worse.”

Blair’s short, often humorous remarks were disrupted by four protesters who stood at the back of the campus mall, carrying signs and shouting words such as “warmonger” at him.

Lawrence Reichard, 53, of Bangor, was arrested and charged with disorderly conduct after police asked him to leave and he refused, according to the Waterville Police Department. Three other protesters who complied when they were asked to leave were not charged.

Blair told the 470 graduates that he would share seven things he’d learned in his life. Among them: be of an open mind, know that giving is as good as getting and learn that friendship matters but nothing matters more than family.

“Be a leader, not a follower,” Blair said. “Above all else, be a doer and not a critic. Human experience has never been shaped by commentators, critics or cynics.”

The 59-year-old Labour Party politician served as prime minister from 1997 to 2007 and was a strong supporter of President George W. Bush’s foreign policy, including the invasions of Afghanistan and Iraq. He now is the head of the Tony Blair Faith Foundation, which aims to promote respect and understanding among the major religions and to make the case for faith as a force for good in the modern world.

The chairman of the Colby College Board of Trustees, Bob Diamond, knows Blair and asked him to speak at commencement, according to Ruth Jacobs, the college’s associate director of communications.

Blair told the students that the world is now more connected than ever before.

“Make use of it,” he said. “It’s a fascinating and energizing world out there. It’s time to explore it.”

And even though they are leaving college and entering a world that seems full of political and economic uncertainty, they should believe in the values of democracy, liberty, free enterprise and fair play.

“This is a time of challenge,” he said. “The 20th century belonged to us. Will the 21st century belong to someone else? Are we an empire that’s fading? My message to you is: have confidence.”

Those values are not a monument to the past, Blair said.

“They are humanity’s best hope for the future. These are the values that inspired the early educators. These values are what brought you here.”

He encouraged the students to be optimistic amidst the challenges and to count their blessings.

“Wake up every morning with a sense of purpose and a thankful heart,” he said. “You have one life, so make the most of it, and by the way, have some fun along the way.”

Blair did not appear to acknowledge the shouts from the protesters.

About a half-dozen men and women were removed from campus by police and security officials after becoming disruptive, Jacobs said.

“They were welcomed to be here as long as they were peaceful and respectful,” she said. “We’re all about the open exchange of ideas.”

One Vermont protester who remained at the back of the crowd said that he was outraged that the campus was welcoming Blair.

“It’s a disgrace for this wonderful school to have this war criminal here,” the man, who did not share his name, said.

Standing next to him was Jody Spear of Brooksville, who carried a sign that said, “Globalization Kills.”

Spear said that she graduated from Colby College 49 years ago and was distressed by Blair’s current efforts to connect globalization with faith.

“I think it’s an absolute travesty,” she said. “That’s what he stands for: the east-west highway. The tank in Searsport. All the things that would link Maine to the rest of the world in the language of globalization. This is not the way life should be in Maine … For him to bring this message of globalization — it’s claptrap.”

In addition to the Colby College graduation exercises, more than 1,000 students from Southern Maine Community College in South Portland were set to graduate Sunday afternoon. It’s the largest graduating class in the school’s 66-year history, according to a press release.

Students from Kennebec Valley Community College in Fairfield, Northern Maine Community College in Presque Isle and the University of Maine School of Law in Portland held graduation exercises on Saturday.