Kennedy, the son of the former senator of the same name who died in 2009, is expected to make the announcement as early as Tuesday, according to the report.
Kennedy Jr. has been mulling a bid since last month for the seat left open by retiring state Sen. Edward Meyer.
Last month, he said he was seriously considering the race.
‘‘I have been encouraged by many friends and civic leaders to consider running for the 12th Senate District seat,’’ Kennedy said at the time. ‘‘I intend to seriously evaluate this opportunity for public service, and to discuss it with my family, close friends and leaders throughout the district.’’
He is the co-founder of the Marwood Group, a healthcare consulting firm. Kennedy left the group several months ago and joined the law firm Epstein Becker Green, where he focuses on healthcare and life science issues. His name has previously been floated for U.S. Senate.
His father, the late Sen. Ted Kennedy (D-Mass.), served in the Senate from 1962 to 2009, when he died. His younger brother, Patrick J. Kennedy, served in the U.S. House, representing Rhode Island, for 16 years before stepping down in 2011.
At least one member of the Kennedy family has held elected office for the better part of six decades, aside from a brief hiatus from 2010 to 2012.
Meanwhile, Rep. Joe Kennedy (D-Mass.), the grandson of Robert F. Kennedy, launched his reelection campaign for the House over the weekend. He was first elected in 2012 in Massachusetts.