Ruth "Kay" Castaldo, 67, an opera director whose imaginative ways helped define the genre during a key period in Philadelphia, died Monday, Aug. 1, in Edgewood, N.M., after battling a brain tumor, her agent said.

Kay Walker Castaldo, as she was professionally known, directed productions for Opera Company of Philadelphia, Cincinnati Opera, Teatro Colón, and New York City Opera. Since 2012, she had been associate professor at the School of Music, Theatre and Dance at the University of Michigan.

"She was a wonderful director because she was a great human being and was interested in human relations and human reasons to be," said Bernard Uzan, the director whose agency, Uzan International Artists, represented Ms. Castaldo.

She was an influential member of the creative team during Robert Driver's tenure as chief of the Opera Company of Philadelphia (now called Opera Philadelphia) that, with designer Boyd Ostroff, developed productions of Madama Butterfly (1996, 2002), Norma (1998), The Tales of Hoffmann (1998), Werther (2001), I Capuleti e i Montecchi (2002), Il Trovatore (2003), and The Pearl Fishers (2004).

Driver remembers then-emerging Russian soprano Anna Netrebko "fearlessly navigated Kay's demanding direction of scaling moving stairs while singing" in I Capuleti e i Montecchi, and he praised the director's innovative approach and gentle mien.

"She is probably the only director who never raised her voice," Driver said.

And yet Ms. Castaldo had a strong vision.

"When her sly smile came on, I knew I was in for something that would challenge me," Driver said, "but her preparation and thinking were always so thorough and logical that she made it seem perfectly natural to produce a 'postapocalyptic' Il trovatore in 2003. It was a stunning production, but there were some very nervous board members when they heard the term postapocalyptic."

Born in Cleveland, Ms. Castaldo earned a bachelor's degree in music from Westminster Choir College and a master's of music history and musicology from the University of Michigan.

Uzan said Ms. Castaldo subscribed to the Stanislavski method and worked less on stage movement than on finding meaning in the text.

"The most important thing is the relationship between the characters, and trying to find inside yourself something you can use for the character you are playing," he said.

The 2003 Trovatore by Ms. Castaldo and Ostroff, starring mezzo Barbara Dever, was a particularly smart and satisfying illustration of the approach. Spare sets and video projection close-ups of facial expressions did much to sharpen characterizations.

Ms. Castaldo perpetuated her artistic philosophy, directing productions at the Curtis Institute of Music and Academy of Vocal Arts, where she also taught acting. At the University of Michigan, she directed Ariadne auf Naxos and Die Zauberflöte. To deepen students' understanding of Dead Man Walking, she produced, in person, nothing less than the heroine of the story herself, nun and death-penalty abolition advocate Helen Prejean.

"She brought her finely honed professional interpretive skills and performance expectations to the student's level through exercises she developed to help students find dramatic motivation and expression within their operatic characters," University of Michigan voice professor Stephen West said.

She was known, he said, "as a wonderful colleague and easy collaborator, with a positive, generous, glowing spirit."

Her husband, composer Joseph Castaldo, died in 2000. Ms. Castaldo is survived by two stepchildren, David and Annalisa; a stepgrandson; and four siblings.

A funeral was held Saturday in Akron, Ohio.

Donations in her memory may be sent to ECHO, 17391 Durrance Rd., North Fort Myers, Fla. 33917 (, or Lakemore United Methodist Church, 1536 Flickinger Rd., Akron, Ohio 44312.