Peter Karos got a cold introduction to business management.

Karos, then 15, saw his Greek immigrant dad drop dead of a heart attack while trying to push the family car out of a snowbank one wintry day in 1942.

The next day, the Minneapolis Washburn High School student took over management of the family’s working-class diner and ran it afternoons and nights to support his mom and siblings until he sold the restaurant in 1946 and enrolled at the University of Minnesota.

“He worked from 3 p.m. until 11 p.m., seven days a week,” recalled his son, Paul Karos. “He said it was kind of on skid row, downtown. He treated all the customers well. He never gave some of those guys money so they could drink, but he would make sure they got something to eat. He later won a University of Minnesota speech competition; his talk was about ‘the plight of those on skid row.’ ”

After graduating, Peter Karos worked his way to be president of a community bank. Later in his career, he became legendary stock-trading executive at Piper Jaffray. He died April 30 after a battle with cancer. He was 85.

Karos was best known for nearly 20 years as manager of Nasdaq trading at Piper, beginning in 1976. The traders did business in person or by phone, before the advent of computerized trading.

Piper veterans recall that Karos, who went by the nickname “Zeus,” cautioned young traders that they had to get the best price for the firm, while also meeting their commitment to the retail brokers or another firm jockeying for its best price. He was known for being a tough negotiator and, in the end, for keeping his word on a trade price.

“Zeus, the Greek god,” quipped Steve Berghs, retired head of Piper’s downtown brokerage office.

Berghs and Karos were known for their spirited bargaining over who would get the best price, the trading desk or the retail brokers for their customers. The contest usually would end with a handshake.

“Peter Karos was a wonderful man,” Berghs said. “And he will be missed.”

Paul Karos said his father never forgot some of the down-on-their luck customers he served at his diner. He was a generous confidante and friend to executives, parking lot attendants, mechanics, co-workers or anybody who needed advice or a helping hand. Peter Karos loved to speak to his children and relatives in Greek, reveled in Greek food and culture and was active in his Greek Orthodox Church. In retirement, he attended events with his grandchildren, played cards and golf and wintered in Florida.

Paul Karos, a longtime securities industry analyst who specialized in the airline industry, said his dad counseled him early on that success lies in being “honest and doing the right thing for the customer.”

“He always said, if I got stressed about something, ‘You just have to be Paul Karos. Look at yourself in the mirror if you want to know if you’re doing the right thing. And always try your best.’ I’ve made mistakes … but that look-in-the-mirror [approach] is a pretty good test.”

Funeral services were held on Tuesday.

In addition to his son Paul, Peter Karos is survived by his wife, Artemis, and children Alex, Nick and Tina.