John Stuart Katz, 72, of Society Hill, a film scholar, author, Penn professor, and one-half of a remarkable Philadelphia love story, died of complications from renal failure Friday, Nov. 26, at the Hospital of the University of Pennsylvania.

A movie omnivore whose courses explored film's impact on political change, Mr. Katz coedited Image Ethics, a book about the moral ramifications of documentary films. He was passionate about nonfiction cinema such as Errol Morris' The Fog of War, but, if pressed, would say his favorite movie was Annie Hall.

Mr. Katz cut a jaunty figure at York University in Toronto, where he was on the faculty for more than three decades, and at Penn, where he taught for 13 years in the English department. On both campuses, undergraduates adored the inquisitive professor with the Richard Dreyfuss vitality and curiosity. His students included Francois Girard and Don McKellar, makers of the award-winning Thirty Two Short Films About Glenn Gould; and Ryan Lee, a Hollywood agent.

A native of Cincinnati, Mr. Katz was a pioneer film educator and one-stop movie resource who earned his doctorate in English at Harvard University before publishing his first book, Perspectives on the Study of Film, in 1971. Complementing his professorial duties in Toronto, Mr. Katz served as a movie critic for the Canadian Broadcasting Corp. radio show Arts National and the television culture magazine T.O. to Go. He was a programmer for the Toronto Film Festival. He married, divorced, married a second time, had a son, Jesse, and divorced.

At the Montreal Film Festival in 1993, mutual friends introduced Mr. Katz to Joan Saltzman, a film enthusiast and medical-malpractice litigator from Philadelphia.

Despite their rooting for opposite sides in the 1993 Toronto-Philadelphia World Series, the courtship flourished, and Mr. Katz sought a post at Penn.

Together the couple taught the Penn-in-Cannes course at the annual film festival in France.

When Mr. Katz met Saltzman, he had kidney disease. Doctors said he required dialysis or a transplant.

Shortly after the couple wed in 1997, Saltzman recalled in her 2006 memoir, Mr. Right and My Left Kidney, she agreed to a blood test, hoping she would be ruled out as a candidate for kidney donation. As it happened, she was a perfect match.

As a belated wedding gift, the reluctant Saltzman gave Mr. Katz her left kidney in 1999.

In return, he gave her an Elsa Peretti necklace with a kidney-shape charm from Tiffany. Gradually, the professor whose fatigue had consigned him to lecturing from a chair was again pacing animatedly before students.

Mr. Katz was active during his last decade, consulting for the Philadelphia Film Festival, coediting Image Ethics, teaching, and becoming grandfather to the beloved Max.

On Saturday, Mr. Katz's friend Joe Baltake, a movie critic, eulogized him and his marriage, quoting a line from the movie I Never Sang for My Father: "Death ends a life, but it does not end a relationship."

Mr. Katz is survived by his wife; son; grandson; and generations of students inspired by his lectures.

The funeral is scheduled for 11:30 a.m. Sunday, Nov. 28, at Goldsteins' Rosenberg's Raphael-Sacks, 6410 N. Broad St.