G. Michael Hostage, a former president of Marriott Corp. restaurant operations, will succeed Howard Johnson as chairman, president and chief executive officer of the Howard Johnson Co.

Hostage has been president and chief executive officer of International Telephone and Telegraph's Continental Baking Co. Inc. since 1979. He started in the sales department of Marriott in 1955, moved on to become Washington district manager and left as corporate vice president in charge of Marriott hotels, restaurants and theme parks.

At ITT, Hostage will be succeeded in the Continental Baking Co. post by Lauren H. Batty, president of the company's bakery division since 1979. Batty began his career with ITT as a route salesman at the Indianapolis plant in 1948. He was manager of the regions surrounding Kansas City and New York before being named vice president of Continental Baking.

The announcement of Hostage's appointment, scheduled to take effect at the first of next year, was made last week in London by Imperial Group Ltd., which owns the Howard Johnson Co. Imperial is the largest tobacco company in Britain and has interests in wines, beers, paper and plastics in addition to the restaurant and food holdings that include the Howard Johnson division.

Hostage will control the restaurant group of Howard Johnson, which has more than 1,000 establishments, such as the Ground Round and Red Coach Grill chains, and will be in charge of the accommodations group of more than 500 hotels. The division is represented in 40 states, Puerto Rico and Canada.

Howard Johnson will serve as a consultant to Imperial until June 1985.