Los Angeles police said the crash happened on Los Angeles Street north of 17th Street at about 11 a.m.
According to the fire department, 55-year-old Jerome Boyd, a 30-year veteran of the department and a battalion chief, suffered a medical emergency while driving and crashed.
Boyd was rushed to the hospital where he died. At the time of his death, officials said Boyd was assigned to the Fire Prevention Bureau's Public Safety Section.
"I join the men and women of the LAFD in mourning Chief Boyd's sudden passing," Los Angeles Fire Department Chief Ralph Terrazas said in a written statement. "It is always an unexpected tragedy to lose one of our own and my thoughts and prayers are with his family at this difficult time."
Fire officials said an autopsy was pending and funeral details would be released at a later date.