Interim Suffolk County District Attorney Kevin Hayden is set to shed the “interim” part of his title next January — but what Hayden has, and hasn’t, done from the DA’s office is being hotly debated by close observers.

Hayden is running with no Republican opposition for a full term as district attorney after defeating fellow Democrat Ricardo Arroyo in the primary this month. He is nine months into the job, serving in place of former D.A. Rachael Rollins, who left to become the U.S. Attorney for Massachusetts early 2022.

Speaking Tuesday on GBH’s Boston Public Radio, Hayden addressed several points of contention, including last week’s firing of his office’s juvenile unit chief, his handling of a transit police misconduct case and lackluster public support from Boston Mayor Michelle Wu.

On the subject of firing his juvenile unit chief, Michael Glennon, Hayden bristled at the notion he was working against the interest of young people.

In a Boston Globe article published last week, representatives for several juvenile justice groups expressed support for Glennon and called the firing “alarming,” questioning Hayden’s commitment to rehabilitation of young adults caught in the justice system.

“When I hear individuals or organizations question my commitment in that regard, or our office’s commitment in that regard, I recoil a little bit,” Hayden said. “I’ve committed my entire career to children and to protecting children in various capacities. I was a criminal defense attorney representing juveniles and a prosecutor handling juvenile cases. There is nothing more important to me.”

Hayden noted that the juvenile unit is made up of several public servants. “One person does not this program make,” he said, adding, “and even if it did, that one person would be me. And my commitment remains steadfast.”

In the weeks leading up to the September primary, Hayden also confronted reports alleging his office was covering up a case of transit police misconduct. Hayden has strongly pushed back against the allegations.

He decided to appoint a special prosecutor to oversee the case, a decision he said Tuesday was prompted by a tweet sent out — and later deleted — by the MBTA Transit Police’s official Twitter account. “Hayden tried to dump the matter & got caught,” it read. (MBTA Transit Police have since called the tweet “inappropriate” and an “unintentional use of the police department’s official social media account.”)

But Hayden said he took the message as a cue to shift oversight to an independent prosecutor, Glenn Cunha. Cunha is a former Suffolk assistant district attorney and will assume the responsibilities previously overseen by a grand jury investigation.

“I don’t want to rehash it,” Hayden said. “That next day ... we decided it would only be prudent for us to get a special prosecutor involved.”

Hayden’s also deflected criticism from Wu, who voted for his opponent despite sexual assault allegations against Arroyo that surfaced in weeks leading up to the primary.

Speaking earlier this month on GBH’s “Ask the Mayor,” Wu said the two candidates represented “very different directions” for Suffolk County, but said she respects the decision of voters and is eager to use her platform to “work effectively” with Hayden.

“I have no doubt that we’ll be able to work together,” he said of Wu. “I think that we are both keenly aware of the importance of putting any personal feelings or viewpoints aside in order to do what’s best for Suffolk County, best for Boston, best for all of our citizens.”

Host Margery Eagan observed a “big cloud” over the D.A. primary race and Hayden’s office more generally.

“That’s an extra burden you have coming into this office, isn’t it?” she asked.

“I can’t dwell on the past,” Hayden responded. “I can’t worry about things I don’t have any control over, I can only worry about what’s next. What’s next is us doing the job in the district attorney’s office to the best of our ability.”