Dennis M. Callahan, an Annapolis mayor in the 1980s who was known for his hard-nosed political style, died Feb. 8 at his home in Severna Park after a heart attack. He was 70.

The death was announced by the Anne Arundel county executive’s office, where he served as chief administrative officer.

Mr. Callahan was elected mayor of Annapolis in 1985 and served one term. Previously a Republican, he registered as a Democrat before he ran. During his time as mayor, he took tough stances on crime, creating a controversial drug enforcement unit in the city’s police department that he called the “Delta” squad. He also aggressively tackled what he perceived as failed policies at the city’s public housing authority.

He lost his reelection bid in the Democratic primary in 1989 and made several unsuccessful runs for mayor and county executive in the 1990s.

Mr. Callahan served as director of the Anne Arundel County Department of Recreation and Parks from 1999 to 2006 under the administration of County Executive Janet S. Owens (D).

Mr. Callahan lost the Democratic nomination for county executive in 2006. The winner of the general election, County Executive John R. Leopold (R), appointed Mr. Callahan his top adviser.

“Dennis and I would have our differences,” Mr. Leopold said. “But his candor was always appreciated. The county executive needs an adviser who will offer the unvarnished truth — and Dennis did that.”

Dennis Michael Callahan was born in Baltimore and was the son of a deputy chief in the city’s fire department. He attended the University of Maryland. In the 1960s, he played for the Baltimore Eagles, a now-defunct semiprofessional football team.

After serving in the Army, Mr. Callahan founded a medical laboratory company in the 1960s, which he sold. He later started a tuxedo rental business with five locations. He sold the business when he became mayor.

His first marriage, to the former Linda Shaull, ended in divorce.

Survivors include his wife of 38 years, the former Brenda Evans, of Severna Park; two sons from his first marriage, Colin Callahan of Severna Park and Shaun Callahan of Baltimore; two sisters; and five grandchildren.