Thomas K. Sieg, a Utah restaurateur who was one of the founding partners of the Gastronomy chain, died Monday. He was 70.

Known for ushering in a new era of fine dining in Salt Lake City, Mr. Sieg, along with his business partner John Williams, opened the New Yorker in 1978.

That restaurant eventually spawned the Gastronomy chain of eateries, which included four locations of the Market Street Grill, three Market Street Oyster Bars and three Market Street Fish Markets.

"He was Mr. Hospitality," Williams said. "He was there every lunch and dinner, greeting the customers and making sure they had a good time."

Williams said that more than 100 restaurants in Utah have been started by former employees of Gastronomy.

"Tom was the face of the New Yorker," said David Prows, who spent time in the Gastronomy kitchens and is now the executive chef of the Costa Vida restaurant chain. "He was one of the most incredible gentlemen and brilliant businessman. He understood the industry and how to take care of people."

Mr. Sieg was born in Lexington, Neb. He graduated from Nebraska Wesleyan University and later served a stint in the Navy. He then worked for his alma mater and came to Salt Lake in 1966 to work for the University of Utah, where he eventually became director of development.

He left the university to open the New Yorker with Williams.

In 2006, Mr. Sieg retired from day-to-day management of Gastronomy, and Will Pliler and Joy Bradford became the company's managers. The remaining partners of Gastronomy Inc. are Williams, Tom Guinney and Pliler.

Mr. Sieg is survived by his sister, Sherry Pederson of Fort Collins, Colo.; his brother, Ken Sieg of Lincoln, Neb.; his former wife, Melissa Miller of Seattle, Wash.; two sons, Stephen Sieg and Erik Sieg; and two grandsons, Alexander Berg and Lucas Sieg.

Family and friends are invited to attend a celebration of Mr. Sieg's life Sunday at the New Yorker restaurant, 60 Market St., from 1 p.m. to 3 p.m.