RANDOLPH — About 700 firefighters from across the region gathered Tuesday for a wake to honor Watertown firefighter Joseph Toscano, who died last week after collapsing while battling a two-alarm house fire.

The firefighters were joined by hundreds of mourners who assembled outside St. Mary Catholic Church to pay their respects to Toscano, a married father of five who worshiped in the same sanctuary where his wake was being held.

Lined up in rows of four, firefighters marched into the church in somber silence. The Watertown Fire Department SUV that Toscano drove was parked outside the church, along with a Watertown fire truck outfitted to later bring his body to the funeral home.

In the church parking lot, community members lined up to enter the building and pay their respects.

Watertown deputy fire chief Bob Quinn said Toscano was his “eyes and ears inside the fire’’ for the 12½ years he served as Quinn’s assistant.

As assistant to the deputy fire chief, Toscano gave reports from inside the structure to the deputy chief, stationed outside, about what resources were needed, and where.

“I trusted him completely,’’ said Quinn, who is expected to deliver remarks at Toscano’s funeral Wednesday. “Whatever he told me to do, I got it to him, because I know he needed it.’’

Toscano, 54, was stricken by a medical emergency while inside a burning house at 29 Merrifield Ave., officials have said. Authorities haven’t determined the cause of the blaze, but have described it as accidental.

It is unclear what caused Toscano to collapse.

Toscano joined the Watertown Fire Department in 1996. He was also a master carpenter who relied on his vast knowledge of building construction to help put out blazes, said Rob Mannix, president of Watertown Firefighters, Local 1347.

Toscano was a devoted family man, and a gourmet cook who managed to feed the department on a $5-a-person budget, according to Quinn and Mannix.

The meals included second helpings and sometimes even dessert. Dishes ranged from lasagna and country ribs to chicken cordon bleu and to-die-for bread pudding, they said.

Quinn said Toscano loved Incarnation Camp in Essex, Conn., a summer camp he had attended as a child and where he was later a counselor. His own children attended the camp as well.

He was an involved camp alumni, visiting each spring to run a fishing derby for the alumni’s children, according to Quinn.

“There are all these kids out there who know how to fish because Joe Toscano taught them,’’ said Quinn as mourners streamed into the church nearby. “He loved giving back.’’

Cardinal Sean P. O’Malley, archbishop of Boston, attended the wake.

Randolph police said they planned to close at least one lane of North Main Street between Cottage and School streets beginning at 2 p.m.

Following the wake, which ended at 8 p.m., Toscano’s body remained inside the church, where firefighters were expected to stand watch all night, police said. His funeral Mass is scheduled for 11 a.m. Wednesday at St. Patrick Roman Catholic Church in Watertown.

The funeral procession is planned to depart Randolph at 9 a.m., police said.

The Watertown church hosted the funeral Mass for Boston Fire Lieutenant Edward Walsh Jr., who died with firefighter Michael Kennedy while fighting a massive blaze on Beacon Street in the Back Bay on March 26, 2014.

The Rev. Ron Coyne, the former pastor at St. Mary, has said he plans to celebrate Toscano’s funeral Mass. Remarks are expected to be delivered by Quinn, Toscano’s childhood friend Marcus DeFlorimonte, and his children, according to a funeral program.

Auxiliary Bishop Robert P. Reed of Boston plans to attend on behalf of O’Malley, who will be in Rome on Vatican business, a spokesman said.

A charitable fund has been established on behalf of Toscano’s family, a Boston Fire Department spokesman said. Donations should be directed to the Watertown Firefighters Relief Association/Toscano Fund at 99 Main St., Watertown, MA 02472.

Nicole Fleming can be reached at nicole.fleming@globe.com. Laura Crimaldi can be reached at laura.crimaldi@globe.com. Follow her on Twitter @lauracrimaldi.