After walking away from his decades-long policing career to focus on his heart health last fall, former Newton Police Chief John Carmichael says he is ready to serve his community again.

On Sunday, Carmichael, 57, visited the Boston Marathon finish line in Copley Square with his one-year-old Golden Retriever, Aine, healthy and determined for the future.

More than half a year after he resigned from the Newton Police Department, Carmichael said his health has made “great strides” as he is exercising consistently again and no longer has a heart monitor. The community stalwart added he is considering pursuing law school or political office at some level.

“I always kept that community policing philosophy,” Carmichael said as he reflected on his 35-year career in law enforcement. “Whatever I am destined for, I want to make sure I continue to help and serve people and my community.”

Monday marks two years to the day since Carmichael collapsed in uniform inside the Newton Police Department before being rushed to Beth Israel Deaconess Medical Center in Boston, where doctors ultimately determined he had an undiagnosed heart condition.

His collapse came days after the running of the 2023 Boston Marathon, an event that prompted immediate racial profiling and harassment complaints and eventually a federal lawsuit against the department and the Boston Athletic Association.

A federal judge threw out the complaint against Carmichael last month, at the same time advancing parts of the suit against the B.A.A. and Newton Police.

“I didn’t leave the job because of the lawsuit,” Carmichael said. “I left the job against all of my desires, but if you don’t have your health, you don’t have anything.”

In the underlying incident, Newton Police responded to Heartbreak Hill at Mile 21 after receiving three notifications from the B.A.A. about spectators crossing over a rope barrier, some getting in the way of runners at the toughest stretch of the 26.2-mile course.

Two Black community running groups, the TrailblazHers Run Co., behind the federal discrimination complaint, and Pioneers Run Crew, alleged Newton Police engaged in  ‘racially targeted overpolicing’ after officers with bicycles lined up at their cheering spots, restricting their ability to give out high-fives.

Police officers also took positions behind the group’s tent.

Carmichael said  the officers “were very professional and did their jobs. Frankly, they did what they were trained and expected to do, and that is to keep the racecourse safe, keep people back who were going out onto the course.”

The allegations of racial profiling spread on social media hours after the marathon, and reporters from all over the country started calling the department a day later, Carmichael recounted. He said he instructed his staff to work with the media “to get the facts out there.”

After working “around the clock” in the days that followed, Carmichael said he remembers he had just gotten out of a meeting and was about to leave the police station that Friday. Suddenly, he felt “disoriented” and “dizzy” before he fell into a set of chairs and a table. He’d collapse again, hitting his head against a door.

Carmichael recalled feeling “embarrassed” and “confused” as he woke up in an ambulance that was rushing him to Beth Israel in Boston.

“I got there, and all I remember was my heart still hurting and being cold; I was shivering,” he said as he paused. “It’s just emotional, you know?”

Carmichael stayed at the hospital for four days as doctors determined he had an undiagnosed heart condition, which he said was exacerbated by the stress of the racial profiling allegations. Medical personnel inserted a heart monitor in his chest before he left.

A month later, Carmichael’s sister died from a heart attack at age 52. He said his father had also died from a heart attack.

When he  returned to work following his hospital stay, Carmichael said he met twice with the groups that argued his officers mistreated them, having “honest conversations.”

“For something like this to happen, it was very disheartening,” Carmichael said of the 2023 altercation, “not just for me, but for the officers who were there that day, working very long hours, providing security for one of the best and most incredible events that Massachusetts has.”

In response to the altercation, the B.A.A. has added more barricades to the course, and its app for tracking friends and family has a “Spectator Guidelines” section. People who download the app have to go over the code of conduct rules before following runners.

Carmichael said he had never spoken with the media about the events of the past two years before he opened up with the Herald.

“Statistically, police officers don’t have a long life course, especially if they stay in policing and retire, they’re very susceptible to heart attack,” he said. “I am very cognizant of that. At some point, I will probably start to tell more people my story so they can protect themselves.”

Former Newton Police Chief John Carmichael (Nancy Lane/Boston Herald, File)