Baruch College alumnus and community college professor Jack Mandel died at the age of 73 due to heart complications, Business News reported.

Mandel served as a mentor to over a thousand students throughout his long career, an education career that spanned over 50 years. Mandel earned a bachelor’s degree in business administration from Baruch and he later went on to earn a master’s degree in business administration.

Mandel’s 50-year teaching career began in the New York City public school system, before he went on to become a professor at Nassau Community College. Mandel’s Nassau Community College, or NCC, teaching days began in September 1978.

He taught a number of business courses while employed at the Long Island college.

Mandel’s achievements include being the recipient of the Outstanding Teacher Award by the New York State Association of Two-Year colleges. Mandel was also the recipient of the NCC Faculty Distinguished Achievement Award.

Mandel also served as author of the Professor Mandel’s Long Island Arts, Fine Crafts and Collectibles Directory.

He was also an occasional contributor to The Long Island Business News. He most notable work was a 2019 column called, “How to attract all the business you need,” where he offered readers business advice.

“In the real world, there are no such things as: High quality or low quality; great service or poor service; a good deal or a bad deal. Only the customer’s perception makes it so,” Mandel said in his 2019 column. “It’s not what you know but what they perceive that counts. When it comes to marketing, how you perceive your business is irrelevant. How customers perceive your business is everything.”

Mandel was also a contributor to The Long Island Weekly.

In 2018, Mandel wrote a piece called “How Do You Define Success?” where he listed five attributes to gaining success in the business world. Among the list of attributes are “self-confidence.”

“People evaluate you by their perception of your worth,” Mandel wrote. “Your actions and words should reflect a strong belief in yourself.”

According to Long Island Business News, Jason Mandel, Mandel’s son, delivered a eulogy for him.

“He loved his job so much and said it never really felt like work to him,” Jason Mandel said. “My dad loved his students and felt it was his calling to impart his knowledge to them.”

Jack Mandel is survived by his wife of 35 years, Ronnie Mandel; his sons and daughters-in-law Jason and Dana; Joshua and Julie; Jordan and fiancé Valerie; and Jaron and fiancé Dana. He also leaves behind three grandchildren, Grant, Skylar and Lucas.