Mr. Busch died at the University of Maryland Medical Center in Baltimore, where doctors were treating him for pneumonia. His office said he agreed Saturday to use a ventilator to help him breathe, but his condition on Sunday took a turn for the worse.
“At 3:22 p.m. this afternoon, Maryland Speaker of the House Michael Erin Busch passed away peacefully, surrounded by loved ones,” Alexandra M. Hughes, his chief of staff, said in a statement.
He had announced his illness a week ago and told colleagues he could miss the rest of the General Assembly session, which ends Monday. The pneumonia was diagnosed after Mr. Busch underwent a follow-up procedure to his 2017 liver transplant.
Known as a pragmatist, Mr. Busch, an Irish American Catholic, evolved on his positions throughout his tenure, including his once-staunch opposition to expanding gambling in the state.
He presided over a progressive agenda as speaker that included ending the death penalty, decriminalizing small amounts of marijuana, legalizing same-sex marriage and in this session raising the minimum wage to $15 an hour.
Mr. Busch recently led the legislative charge to bolster education funding in the state to new levels.
“I’d like to think that when my time is done here, whenever that may be, that we’ve made every effort to make Maryland’s school system the best in the country,” Mr. Busch said in an interview with The Baltimore Sun during his final session.
A history teacher and varsity sports coach at St. Mary’s High School in Annapolis before transitioning to government work, the Democratic Anne Arundel County delegate was selected as speaker by his peers in 2003 after the election defeat of Casper R. Taylor Jr. In 2012, Mr. Busch became the longest-serving speaker, surpassing the tenure of Mr. Taylor, who had been an ally and mentor. Upon learning of Mr. Taylor’s defeat, Mr. Busch called colleagues through the night to shore up their support. When rivals for the post began working the phones the next morning, they were too late.
Mr. Busch, a longtime Annapolis resident, was a patient consensus-builder who acted like the coach of a team. Some colleagues even called him “Coach.”
Republican Gov. Larry Hogan said in a statement that Mr. Busch was “a giant in our government.”
“He cared deeply about improving the lives of Marylanders, and his legacy is evident in his many legislative achievements. Speaker Busch and I came from different sides of the aisle, but we often came together in the best interests of the people of Maryland. He served with the decency and good nature of a teacher, a coach, and a family man. I was honored to know him and to work closely with him.”
Mr. Hogan ordered Maryland’s flags to be lowered to half-staff.
“Mike has been a friend for years, and has led the state to new heights of environmentalism and education, while ensuring that a new generation of leaders move our state forward,” Senate President Thomas V. Mike Miller said in a statement. “He was a true model of a state delegate; he cared for every corner of the state, but never forgot about the people he was elected to represent. I will miss him as a friend and partner in state government.”
Mr. Busch was the sponsor of a bill this session to permanently bar oyster harvesting in five waterways targeted for the restoration of the distressed species. Mr. Hogan vetoed the bill, but the House voted Friday to override his veto and the Senate was expected to do the same Monday.
The Chesapeake Bay Foundation’s Maryland Executive Director Alison Prost issued a statement, mourning Mr. Busch as a “champion” of the bay.
“While there were many issues that were near and dear to Speaker Busch, he elevated saving the bay to a priority for the General Assembly, and legislators followed his lead,” she said.
House Minority Leader Nic Kipke, an Anne Arundel Republican, called Mr. Busch’s death “sad and surreal.”
"He was a good man and a dear friend. The coach-like style that he brought to his speaker-ship lifted all of us up and made us better people and better legislators,” Mr. Kipke said in a statement. “He liked to win, but what he wanted most was to see everyone 'play the game' fairly, with honor and dignity."
First elected to the House as a representative for District 30 in 1987, Mr. Busch later became a committee chairman and helped shape the laws of Democratic-dominated Maryland on gun control, health care and other issues for decades.
D. Bruce Poole, a former chairman of the Maryland Democratic Party, was a close friend. The two men met after they had both been elected as delegates and Mr. Poole recalled in a phone interview Sunday that he wondered what a muscle-bound football player was doing in the legislature.
“People were kind of snide about him,” Mr. Poole remembered. “They don’t think he could understand complex matters of health care and workers’ compensation.”
But Mr. Poole watched his friend grow into a skilled committee chairman, widely liked and respected because of way he treated his colleagues.
“He went from the back-bencher jock to becoming a committee chairman,” Mr. Poole said. “He gave everybody respect and their due. In his wildest dreams, he never thought he could be speaker, and ended up being the longest-ever serving speaker in the state of Maryland.”
Mr. Busch was a leader in the effort when Maryland banned assault rifles in 2013 after 20 children and six staff members were shot to death at Sandy Hook Elementary School in Newtown, Connecticut.
He helped enact a program to help seniors pay prescription drug costs, and fought to preserve health insurance for people with pre-existing medical conditions.
Mr. Busch, once a star running back at Temple University in Philadelphia, was beset by health problems during his later years, losing considerable weight.
Doctors diagnosed him with nonalcoholic steatohepatitis in 2017. By then, Mr. Busch, a nondrinker, had packed 16 liters — 30 pounds — of fluid on his abdomen. He couldn’t take off his shoes. He received the liver transplant from his sister, Kathleen “Laurie” Bernhardt.
“I was going to do everything I could to live. I have two daughters,” he said after the transplant.
He had heart bypass surgery in September at the University of Maryland Medical Center.
Despite his health challenges, the members of the House unanimously elected him speaker again in January. Democratic Del. Joseline Pena-Melnyk nominated Mr. Busch, calling him “a person of great integrity” and “a great coach for the General Assembly” — a nod to his life experience and his leadership style. Del. Adrienne Jones of Baltimore County was re-elected as speaker pro-tem, a position that involves substituting for the speaker when he is absent, and she has filled in for Mr. Busch during the session when he has been ill.
To support him through his battles with health problems, members of his staff wore bracelets reading “Iron Mike.”
When Mr. Taylor lost his seat in 2002, many in Annapolis expected the Mr. Busch to be overwhelmed by a combination of long-tenured Senate President Miller and a new Republican governor, Robert Ehrlich.
But a battle was joined in 2003 over the issue of slot machines, with Mr. Miller and Mr. Ehrlich in favor of allowing them at racetracks. While Mr. Miller was an irresistible force on the issue in the Senate, strong-arming a bill through his chamber, he ran into an immovable object in the House. Personally opposed to slots and skeptical of a plan he considered a giveaway to the racetracks, Mr. Busch defeated the legislation that year. For the rest of his term, Mr. Ehrlich was unable to forge a plan that Mr. Busch and Mr. Miller could agree on. Not until Gov. Martin O'Malley, a Democrat, took office in 2007 was a deal on slots made.
Del. Maggie McIntosh, a Baltimore Democrat who is chairwoman of the Appropriations Committee, noted Mr. Busch appointed a diverse group of delegates to leadership positions.
“He opened up the doors to leadership to people who were black and white and brown, gay and straight, female and male,” Ms. McIntosh said. “He gave access to everyone. That was something that didn’t exist before.”
After the vote to legalize same-sex marriage in Maryland, lawmakers who had long sought the change applauded Mr. Busch. Del. Heather Mizeur — an openly gay Montgomery County Democrat — famously kissed him on the cheek in a moment of celebration.
Mr. Busch had little tolerance for powerful groups he perceived as unjustly enriching themselves, Ms. McIntosh said. In his final session, Mr. Busch worked to fix problems and instill ethical standards at institutions after scandals around the state, she said.
Mr. Busch reacted swiftly after learning of no-bid contracts awarded to some members of the University of Maryland Medical System board of directors, of which he was a member, and pushed for emergency legislation to reform the board.
“He has such integrity,” Ms. McIntosh said. “He sees a mess. He cleans it up.”
Mr. Busch was born in Baltimore and graduated from St. Mary's in Annapolis. He received a degree in education from Temple. He attracted attention from the NFL before sustaining a knee injury that ended his hopes of going pro.
Mr. Busch worked as a teacher and coach at his old high school for several years before becoming administrator for youth athletics in the county recreation department.
Mr. Busch is survived by his wife, Cindy, and two daughters. Erin Busch is a recent graduate of Stetson University, where she played on the women’s lacrosse team. Her sister, Megan, is a student at Coastal Carolina University and also plays lacrosse. Mr. Busch also survived by his sisters, Ms. Bernhardt, Gail Burkhead and Susan Evans.
Baltimore Sun reporter Pamela Wood contributed to this article.