Sims, who has worked at the Cheyenne, WY based Mexican restaurant chain since 1986 in a variety of capacities, has most recently served as executive vice president and chief financial officer.
Sims grew up in Vermillion, and his mother, Elaine McNulty, still lives here. "I am both humbled and highly honored to receive this appointment. Taco John's has been my home for more than 20 years, and I have great admiration for our owners, franchisees and employees," Sims said in a prepared statement.
"I'm pleased that I'm able to continue working with all these great people who share my passion for our business, and I look forward to achieving new heights with the Taco John's brand," he said.
Sims replaces Paul Fisherkeller, who will remain with the company as chief executive officer and chairman of the board.
The move comes as a result of succession planning at the Cheyenne company, spokesman Brian Dixon said. The goal was continuing the company's record of success in the future.
"We looked at it comprehensively, from the human resources and organizational vulnerability, and put some processes in place to elevate people's skills," Dixon said.
"We looked at the leadership in the company and did some wonderful things."