"I don't remember the party either," Obama said. "I'm just telling the truth here."
Obama's remarks to the graduating class at Worcester Technical High School in Worcester, Mass., turned more inspirational after that opener.
"Your journey is just beginning," he told them.
"Each of us is only here because somebody, somewhere, invested in our success," he went on.
For students at Worcester Tech, one of those people is an English teacher the president referred to only as "Mr. O'Connor," who, he suggested, has a reputation for classroom rigor.
"Everybody's got to have a Mr. O'Connor in your life, just to straighten you out," said Obama, who doesn't gloss over the fact that he was a partyer in high school.
Something has straightened out Worcester Tech. Formerly one of Massachusetts' lower-performing vocational schools, the school has seen its standardized test scores and graduation rates rise dramatically in the last few years.
In 2013, it won the Department of Education Blue Ribbon award for significant improvement. Principal Sheila Harrity has earned a national award for her work turning things around.
As he paid tribute to those achievements, Obama praised college affordability legislation sponsored by Massachusetts Sen.
The words came a little late, though. The measure failed to overcome a Republican filibuster in the Senate to advance on Wednesday.
"Maybe they've forgotten where they came from," Obama said of the measure's opponents.
As he spoke, the president said he hadn't forgotten the people who helped him along -- nor those who are his responsibility today.
Two years from now, his older daughter, Malia, is due to graduate from high school, and he said the thought of it made him teary. He said the commencement speech was a "trial run" so he could practice not choking up and crying.
In closing, he urged the students to keep "blazing a trail" for others to follow -- even if they don't remember their graduation address years from now either.
"You don't need to remember what I said today," he said. "Because you're already doing it."