Michael Lupu, the plucky polymath who, as senior dramaturg, helped shape scores of shows over three decades at the Guthrie Theater, died Thursday in Minneapolis.

He was 89.

He had “such a formidable intellect — such a fun and wicked sense of humor,” said Guthrie artistic director Joseph Haj, who was a young actor at the theater when Lupu was in his heyday. “He was such a deep and incisive reader of plays, one of the best dramaturgs I’ve ever, ever been around.”

Dramaturgs combine the roles of researcher and editor with in-house critic. Their work often goes unnoticed, unless some glaring error or cultural inappropriateness makes it to the stage.

Lupu helped redefine and expand the definition of a dramaturg, not just at the Guthrie, but nationally and internationally, said influential dramaturg and theater artist Mark Bly. Bly worked with Lupu as head of the Guthrie’s dramaturgy department from 1981 to 1989 and was head of playwriting at the Yale School of Drama from 1992 to 2004.

“He and I pioneered a new kind of dramaturgy that was not hidebound research but active collaboration in the rehearsal hall,” Bly said. “We helped shape the directorial, acting, design, textual, research and historical values of a production. That became known as Minneapolis dramaturgy.”

In 2006, Lupu won the field’s highest honor, the Lessing Award, named for German playwright and critic Gotthold Ephraim Lessing, the world’s first dramaturg.

Compact with a ponytail, Lupu was often seen loaded down with books. He cut an almost gnomic figure — both in his stature and in his wisdom. But he was a giant, said Marcela Lorca, the Guthrie’s former movement director. She worked with Lupu for 22 years, starting in 1991.

“He was fun to have in a room, and the room was sacred, and safe, because of his presence,” Lorca said

Lupu spoke at least seven languages, including Russian and Yiddish, and he had an encyclopedic knowledge of world history and culture.

Called Miki by his friends, he was born in 1930 in Romania. In Romania, he became a film critic and theater artist before immigrating to the United States in 1972.

He would go on to earn a master’s degree at the Annenberg School for Communication at the University of Pennsylvania.

Lupu arrived in the Twin Cities in 1981 — the year his Romanian countryman Liviu Ciulei assumed the artistic reins at the Guthrie — first working in community outreach. But he quickly put his encyclopedic knowledge to broad use as he joined the theater’s literary department, which used research to contextualize and support plays.

“The theater rehearsal room was intimate, hilarious and full of intellectual challenge and warmth as you try to unpack a play in order to understand it then repack it for the audience,” said Peg Guilfoyle, an author and production director who worked with Lupu from 1981 to 1989. “Michael was at the very center of that fire, full of wit, wisdom and a profound sense of play.”

Lorca, who taught in the Guthrie Theater/University of Minnesota BFA program, would regularly invite Lupu to talk to her students.

“He spoke in long strings of thought that would take you through mazes and lead you more to a feeling than a logical conclusion,” Lorca said. “He was complicated, effervescent, intelligent and deeply human.”

His survivors include a daughter, Anca Livnat, and two grandsons, all of Israel. Services are pending.

Staff writer Chris Hewitt contributed to this report.