“There is a grave disconnect between our culture in the classroom and the behaviors outside of it,” Dartmouth College’s president, Philip J. Hanlon, said Wednesday. (Scott Eells/Bloomberg)

Dartmouth College’s president lamented Wednesday that the Ivy League school’s promising future “is being hijacked by extreme behavior,” including sex assaults, parties with “racist and sexist undertones,” and a campus culture in which “dangerous drinking has become the rule and not the exception.”

Philip J. Hanlon, a Dartmouth alumnus who took office in June, said such problems were taking a toll on the image of the 245-year-old college in Hanover, N.H. Applications to Dartmouth fell 14 percent this year, the sharpest drop in two decades, and the federal government has launched an investigation of issues related to sexual harassment and sexual violence there.

“The actions I have detailed are antithetical to everything that we stand for and hope for our students to be,” Hanlon said in an advance copy of a speech he was planning to give Wednesday night. “There is a grave disconnect between our culture in the classroom and the behaviors outside of it — behaviors which too often seek not to elevate the human spirit, but debase it. It is time for Dartmouth to change.”

Hanlon’s unusually stark assessment of the challenges facing the prestigious college came as many faculty, students and alumni have been agitating for action to prevent sex assaults and improve the campus climate. But the speech also reflected a larger national debate about campus safety. President Obama this year formed a task force to develop policies to stop assaults, and Hanlon said he and other college presidents met recently with Vice President Biden to discuss the topic.

“These are issues that are clearly bedeviling every campus in this country,” Hanlon said in a telephone interview before the speech, “and every president is worried about them.”

Asked whether he also worries about shining a spotlight on Dartmouth’s troubles, Hanlon said students and parents should take heart that the college is mobilizing to address its problems.

“These are issues everywhere,” Hanlon said. “A prospective student or parent should be concerned if a campus is not talking about them.”

Dartmouth, the smallest Ivy League school, has about 6,300 students. Its world-class academic reputation from time to time has been shadowed by image problems related to fraternities and rowdy parties of the sort satirized in the 1978 movie “Animal House,” which was based in part on a Dartmouth fraternity.

Dartmouth fraternities came under scrutiny in a 2012 Rolling Stone article that offered an inside account from a former member of the Sigma Alpha Epsilon fraternity. Among the hazing abuses, which Andrew Lohse also alleged in an op-ed published in a campus newspaper, were that pledges had to “swim in a kiddie pool of vomit, urine, fecal matter, semen and rotten food products; eat omelets made of vomit; [and] chug cups of vinegar.”

Sexual assaults also have drawn attention. The college disclosed last fall that its safety department had received reports of 24 forcible sex offenses in 2012, up from 15 the year before. The definition of those offenses encompasses forcible rape, sodomy or fondling, as well as sexual assault with an object.

The Education Department confirmed Wednesday that its Office for Civil Rights is investigating Dartmouth’s compliance with a federal law against gender discrimination, with a focus on issues related to sexual harassment and sexual violence. Department spokeswoman Dorie Nolt would not elaborate on the Dartmouth probe. But she said the office is investigating allegations of sexual violence at 53 colleges and universities across the country.

Dartmouth is moving to strengthen its sex-assault investigations. A proposal under review would refer cases to a trained external investigator, rather than an internal committee that typically handles disciplinary matters. It also would require mandatory expulsion for the most severe sexual offenses, such as “cases involving penetration accomplished by force, threat, or purposeful incapacitation.”

College officials say a new disciplinary system for sex assaults will take effect by June.

Hanlon also said he will convene a committee of students, faculty, administrators and alumni to draft reforms to end sexual assault, high-risk drinking and other harmful behavior. The committee will be asked to submit recommendations next fall.

“We can no longer allow this college to be held back by the few who wrongly hide harmful behaviors behind the illusion of youthful exuberance,” Hanlon’s speech said. “Routinized excessive drinking, sexual misconduct, and blatant disregard of social norms have no place at Dartmouth. Enough is enough. I am calling on us to create fundamental change in every place on campus where social activities take place — residence halls, Greek Houses, Affinity Houses, Senior Societies, and other campus organizations.”

Susy Struble of Piedmont, Calif., a 1993 graduate active in an anti-sexual-violence group called Dartmouth Change, said Hanlon’s actions seemed promising. But she said: “We’ve had such discussions, and community-led discussions, and summits and recommendations before. This time could be different, and I hope that it is.”