Frank J. Leonard was a longtime minor league baseball manager, with a career lasting from 1887 to 1913.
He first managed the Manchester Farmers of the New England League in 1887.
In 1894, he managed the Pawtucket Maroons of the New England League.
Leonard managed the Columbus Senators of the American Association in 1903.
He last managed the New Brunswick-Maine League's St. John Marathons.