State Representative Harold P. Naughton Jr., a military lawyer who has served in Iraq and Afghanistan, will kick off his campaign for attorney general Thursday, becoming the second Democrat vying to replace Martha Coakley, who is running for governor.
Naughton will join a field that currently includes Maura T. Healey, who stepped down from her position as a top aide in Coakley’s office to launch her run for attorney general.
Naughton, 53, had been exploring a run for lieutenant governor, but said he decided to enter the race for attorney general instead because it is a better fit for his experience.
“I can use the skill set that I’ve built up over the years, through hard work, to run that office and run it successfully,” he said Wednesday.
He plans to launch his campaign Thursday with a Web video and a statewide tour Thursday and Friday.
A Clinton resident, Naughton received his law degree from Suffolk University and then worked for three years as a prosecutor in Worcester County, handling drug, assault, and vehicular homicide cases.
In 1995, he was elected to the House of Representatives, where he is chairman of the Committee on Public Safety and Homeland Security. In that role, he has been drafting gun-control legislation that is expected to be a major topic of debate in coming months.
After the attacks of Sept. 11, 2001, he joined the Army Reserve and served one tour in Iraq and one in Afghanistan.
As a major in the Judge Advocate General’s Corps, he said, he has helped establish judicial and law enforcement systems in southern Afghanistan and advised the Congolese Army on anticorruption procedures.
In 2011, Secretary of State Hillary Rodham Clinton named Naughton to the International Security Advisory Board, which advises the State Department on arms control and other issues. Clinton’s successor, John F. Kerry, recently reappointed him to the board.
Naughton said his proudest accomplishments as a legislator include laws he sponsored that extended death benefits to volunteer firefighters killed in the line of duty and that broadened veterans’ benefits.
If he is elected attorney general in fall 2014, Naughton said he would focus on gun violence, cybersecurity, bullying, drugs, and wage-enforcement laws, among other issues.Michael Levenson can be reached at mlevenson@ globe.com.