Michael Sullivan, clerk of courts for Middlesex County, said he planned to run for Middlesex District Attorney, setting the stage for a contested Democratic primary next fall with incumbent Marian Ryan.
Sullivan, 54, told the Lowell Sun that he planned to make a formal announcement of his candidacy early next year.
A former city councilor and mayor of Cambridge, Sullivan has been the elected court clerk since 2007. He said his experience would make him a strong candidate for district attorney.
Ryan, 58, is seeking election to a full four-year term after being appointed earlier this year by Democratic Governor Deval Patrick to fill out the remainder of Gerard Leone’s term as district attorney. Leone resigned to join a private law firm.