When Maja Matarić was pregnant with her third child and told her boss, Viterbi School of Engineering Dean Yannis Yortsos, his face lit up.

“He was so happy for me because … to him it was all about ‘This is a wonderful thing. I’m so happy for you. I’m a parent. You’re a parent. This makes you happy,’” said Matarić, then-Viterbi vice dean for research. “He never thought for a second how this impacts him or his team, which is what 99% of other people would have done.”

Matarić, now a professor of computer science, neuroscience and pediatrics, said that is just one story that encapsulates who Yortsos is as a person. In an interview with the Daily Trojan in February, she described the soon-to-be former dean as “caring,” “discerning” and “humble.” 

After the longest tenure of any engineering dean at USC, Yortsos will leave the role and return to the Viterbi faculty on July 1, Provost Andrew Guzman announced Feb. 2. During Yortsos’ 21 years as dean, the school launched the School of Advanced Computing, opened the Ginsburg Human-Centered Computation Hall, achieved gender parity in entering classes and diversified its faculty. 

“I offer my sincere gratitude for his transformational contributions as Dean and for his total of 25 years serving in the Viterbi dean’s office. Dean Yortsos’ true legacy is the strength of the Viterbi School,” wrote Guzman in a community-wide message.

Yortsos rose to the deanship after then-Dean Max Nikias became USC’s provost. Before his promotion, he served as a professor of chemical engineering and petroleum engineering, associate dean of academic affairs for Viterbi and senior associate dean for academic affairs.

He received his undergraduate degree in chemical engineering from the National Technical University of Athens in 1973. Yortsos went on to get his master’s degree and Ph.D. in the same subject from Caltech in 1974 and 1979 before joining the Viterbi faculty in 1978

“Like many before and after me, I was warmly, unconditionally welcomed and embraced by a country that offered an inspiring environment to work, grow, and prosper,” wrote Yortsos in his LinkedIn post about receiving the USC Presidential Medallion on April 13.

The award honors those who “greatly contributed to USC in areas that promote the excellence of the institution.” Yortsos was one of two awardees in 2026.

Yortsos hired about 63% of Viterbi’s 213 tenure and tenure-track faculty, according to Timothy Pinkston, vice dean for faculty affairs. Pinkston said that Yortsos helped diversify those roles, including hiring more women, Black and Latine faculty members.

“He was authentically and passionately about … the importance and need for persons from all parts of our diverse population to get training in engineering,” Pinkston said. “I saw his passion and his genuineness on this particular topic, and it compelled me and motivated me to want to work for such a person.”

During Yortsos’ tenure, Pinkston said Viterbi gained nearly 90 endowed professorships, while 28 faculty members were elected to the National Academy of Engineering, according to Guzman’s email. Yortsos was also dean when the school reached gender parity in its entering class in 2019 — a milestone the school reported has continued through at least 2025.

Matarić, who worked in the dean’s office for 13 years, said she appreciated being able to express when she disagreed with Yortsos as a member of his leadership team. 

“He appreciates a diversity of opinions,” Matarić said. “I’m a firm believer in just being very open with ideas and potentially critiques. And Yannis has always embraced that, which is very impressive, because most people don’t want that.”

She said that most people wouldn’t know from first meeting Yortsos that he’s still very engaged with research.

“One of the things that’s really sweet about Yannis is that he’s such a nerd,” Matarić said. “If you just talk to him about his work, he’ll, even all these years later, talk about his research, and all this nerdy stuff that — I don’t know anything about, so don’t ask me — but he’s so happy to explain it.”

At a recent panel on harnessing artificial intelligence to advance sustainability, Yortsos said a major goal of the school is to create graduates with a strong sense of ethics.

“The most important thing is to make sure that we educate our engineers, for example, to have values that are human values, and therefore they are imposed to some extent, at least to the application of AI at USC,” Yortsos said. “We’re trying to, for a while now, to educate engineers with what I call both outstanding competence and outstanding character.” 

Gaurav Sukhatme, executive vice dean and director of the School of Advanced Computing, will serve as interim dean of Viterbi after Yortsos steps down, according to Guzman’s Feb. 2 email.

“It’s a pivot point. It’s a loss for the school in that he’s done so much, and I think he could continue to do a great job. I think he could have continued to have elevated the school in many ways,” said Pinkston. “Of course, this is an opportunity for a different leadership.”