After graduating with a general business degree from the University of Florida in 1978, Kalt along with his brother Jeffrey, developed a six-unit chain of casual Italian restaurants in East Tennessee called "The Best Italian Restaurant". After six years, Kalt sold out to his brother and returned to his native New York.

Through a friend, Kalt met famed Chef Daniel Boulud, who had just received Four Stars from The New York Times at the helm of Le Cirque in New York City. Boulud hired Kalt in March of 1987, where Kalt worked his way up from Chef Degustation to Chef Saucier over a two year period. The skills Kalt acquired from Boulud's tutelage eventually led to a Chef de Cuisine position at the nationally recognized Arcadia restaurant under renowned Chef Ann Rosenzweig.

Following his experience as a multi-unit operator and years of training at Le Cirque and Arcadia, Kalt joined with partners in 1990 to start a hospitality consulting business based in New York City. Kalt, along with Ken Friedman, an experienced Public Relations executive, and Andrew Zimmern, an expert in BOH systems and operations, formed Epicus Group, focusing on food, service, systems and design development for restaurants. Kalt later branched out to work independently from the group forming Stephen Kalt Associates (SKA) in 1992, bringing in associates on a project by project basis.

Immersed in the development of a myriad of casual and fine dining restaurants ranging from Kelly and Ping, a Hong Kong noodle bar, to Fresco and Torre di Pisa, Italian concepts, to Riodizio in New York and Samba Grill in Las Vegas, Brazilian Steak Houses, SKA worked on concept development, business plan development, menu development, design, as well as systems and service training for start-up and existing restaurant concepts. With the success of SKA, New York Magazine put Kalt on their "Hot List" of people to watch in the hospitality industry in 1993.

In 1994, Kalt became the xo-creator and chef of the acclaimed Mediterranean restaurant, Spartina. With food that was modern Spanish, Provencal, Italian, North African and Eastern Mediterranean, Spartina became an early pioneer of Tribeca, capturing a great combination of neighborhood artists and destination foodies. During its reign from 1994 through 2001, Spartina was named "Top 5 Neighborhood Restaurants in New York" by Food & Wine Magazine, garnered Three Stars from the New York Daily News and Two Stars from The New York Times, in addition to acclaim from New York Magazine, Wine Spectator and Esquire.

Throughout his career, Stephen traveled the Mediterranean region extensively and staged with chefs such as Thomas Keller, Jean George Vongerichten, Wolfgang Puck, Dean Fearing, Robert Del Grande, Martine Berasategui, and Jean Louis Paladin. In the early 1990s, Stephen also developed and taught for two years at a cooking school for ex-addicts and the homeless at Emmaus House in Harlem, New York.

In 2004, Kalt was asked by Steve Wynn to open and develop the modern Italian concept, Corsa Cucina at Wynn Las Vegas. Kalt was responsible for concept creation, development of all menus and recipes, trained all kitchen staff and ran the kitchen. Under Kalt's leadership as Chef/Operator, Corsa Cucina became a must-experience destination in Las Vegas.