The first one took place at the bleakest point of the campaign, the long prelude to the Pennsylvania primary, which was dominated by a furor over Mr. Obama’s former pastor. “We were in the desert, so to speak,” remembered Arun Chaudhary, then and now Mr. Obama’s videographer, who grew up attending Seders with his half-Jewish, half-Indian family.

No one led the proceedings; everyone took turns reading aloud. Mr. Obama had brought Reggie Love, his personal aide, Ms. Jarrett and Eric Whitaker, another close friend, all African-American. Jennifer Psaki, the traveling press secretary, and Samantha Tubman, a press assistant, filtered in. Neither had ever been to a Seder, but they knew the Exodus story, Ms. Psaki from Catholic school and Ms. Tubman from childhood Sundays at black churches.

Image Susan Sher, who is now Michelle Obama's chief of staff, at the White House Seder last year. Credit... Pete Souza/White House

They peppered the outnumbered Jews at the table with questions, which the young men sometimes struggled to answer. “We’re not exactly crack Hebrew scholars,” said Mr. Lesser, now an assistant to Mr. Axelrod.

Participants remember the evening as a rare moment of calm, an escape from the din of airplanes and rallies. As the tale of the Israelites unfolded, the campaign team half-jokingly identified with their plight — one day, they too would be free. At the close of the Seder, Mr. Obama added his own ending — “Next year in the White House!”

Indeed, the group, with a few additions, has now made the Seder an Executive Mansion tradition. (No one considered inviting prominent rabbis or other Jewish leaders; it is a private event.)

But maintaining the original humble feel has been easier said than done.

Ms. Tubman and Desirée Rogers, then the White House social secretary, tried to plan an informal meal last year, with little or even no wait staff required. White House ushers reacted with what seemed like polite horror. The president and the first lady simply do not serve themselves, they explained. The two sides negotiated a compromise: the gefilte fish would be preplated, the brisket passed family-style.