State Representative Jon Santiago formally launched his mayoral candidacy Tuesday after weeks of speculation.

“Today, we set out to bring neighbors together to write the next chapter of our Boston story,” Santiago said in a statement.

Santiago’s campaign released a two-minute video to rally potential supporters around his campaign theme of elevating “Our Boston Story.”

“We are living through an unprecedented crisis, the impact of which will last far beyond today. It’s a turning point for our city, but in it I also see great possibilities,” Santiago said in a statement.

In a statement announcing his release, Santiago touted his life of service and highlighted his work as an emergency room physician at Boston Medical Center, captain in the U.S. Army Reserves and as a state representative.

The 38-year-old Democrat was elected in 2018 to represent the 9th Suffolk District which includes the South End, Fenway, Back Bay and Roxbury, besting long term incumbent Rep. Byron Rushing.

“I see and hear it in the voices of my neighbors, patients, and constituents. I’ve spent my life in service to others and now I’m running for mayor to lead us through this moment and to a recovery rooted in equity and opportunity. I will bring our city back, stronger than ever,” he said.

During the pandemic, Santiago was appointed Vice Chair of the Joint Committee for COVID-19 and Emergency Preparedness Management which he praised as “one of the most productive and progressive legislative sessions in the state’s history.”

“Because like the ER, I don’t only see challenges in Boston. I see hope and courage amidst the crisis,” Santiago said in his launch video. “I know how resilient we are; everyday fighting for a better city. And I’m betting on us. Now let’s write the next chapter of our Boston story.”

Born in Puerto Rico, Santiago's family moved to Boston when he was in elementary school, settling in Roxbury where he said he grew up in subsidized housing and attended Boston public schools.

His family later moved to Texas, and Santiago went to college at the University of Texas at Austin before earning a master's degree in global health at the University of Washington and his medical degree from Yale.

Santiago currently has $159,134 in his most recent filing with the Office of Campaign and Political Finance on February 3.

Santiago joins Councillors Michelle Wu, Andrea Campbell and Annissa Essaibi George who have all formally launched their campaigns.

While he wouldn't compare himself to the other three candidates in the race, Santiago said he would bring a "certain level of crisis leadership" to the mayor's office, as well as a willingness to listen and an "incredible work ethic."

Santiago also declined to offer a detailed assessment of Walsh's tenure as mayor.

"I have tremendous respect for Mayor Walsh. He's a friend and I think he's done a formidable job in his response to the pandemic, but this race isn't about relitigating Mayor Walsh and his performance. This is about who is going to lead Boston," Santiago said.

He said Boston needs to bring students back to school "as soon as possible" and support small businesses who have struggled through the pandemic.

"I've come to learn that my patients are a reflection of Boston. Their stories speak to our greatest challenges," Santiago says in his campaign launch video. "Disparities in health and wealth; rising rents; struggling schools. I've spent my life in service to tackle these very issues."

After college, Santiago joined the Peace Corps where he met and became friends with former Congressman Joe Kennedy III in the Dominican Republic.

He was an active campaigner on behalf of Kennedy during the Democrat's most recent unsuccessful run for U.S. Senate.

Santiago's campaign said it planned a "significant" digital advertising buy for an edited 30-second version of his launch video to run over the next week. Santiago's campaign account has close to $160,000.

Walsh is awaiting confirmation from the U.S. Senate to join President Biden's administration as labor secretary. While it's unclear when that vote might take place or when Walsh will resign, Santiago said he supported, along with the entire Boston delegation, the city's petition to cancel a special election for mayor if Walsh resigns before March 5. That bill passed the House on Monday.

North End Rep. Aaron Michlewitz, the chair of House Ways and Means, also considered a run for mayor but opted against it, as did Suffolk County Sheriff Steve Tompkins and former Police Commissioner William Gross.

Walsh's economic development chief John Barros has also been weighing a possible campaign, according to people close to the 2013 candidate.

State House News Service coverage is included in this article.