Michael G. Fitzpatrick, 56, a longtime Republican politician who rose from Bucks County commissioner to congressman, and whose nonconsecutive terms reflected two of the biggest electoral waves of the last quarter-century, died Monday, Jan. 6, after a battle with cancer.

His death was confirmed by the office of his brother, U.S. Rep. Brian Fitzpatrick.

“My heart is broken. My big brother Mike was my hero and my best friend,” Brian Fitzpatrick tweeted, referencing his brother’s 12-year battle with cancer. “Mike has forever touched the lives of so many in our community.”

During a time of increasing political polarization, Michael Fitzpatrick, of Levittown, was known as a relatively moderate Republican and was popular in his Bucks County district. Representing what was then the 8th District, Rep. Fitzpatrick served from 2005 to 2007 before losing his seat to Patrick Murphy in the 2006 Democratic wave spurred by unrest over the Iraq War. But he won the seat back in 2010 amid the rise of the Tea Party, and held it from 2011 to 2017, serving four terms in total.

Citing a belief in term limits, Rep. Fitzpatrick did not seek reelection in 2016. His brother ran instead and currently holds the seat.

His death drew remembrances from politicians across the state and from the state Republican Party. Gov. Tom Wolf, who said Rep. Fitzpatrick fought “to make our communities stronger,” ordered flags on all public buildings lowered to half-staff.

“Mike proved time and again that it is possible to work across the aisle to make progress while remaining true to one’s principles," said Pennsylvania Republican Sen. Pat Toomey.

Rep. Fitzpatrick had been diagnosed with colon cancer in 2008. He was in remission in 2010 when he ran for Congress again.

“I worked for him when he bounced back and made his second run,” said Rep. Fitzpatrick’s longtime campaign strategist, Michael J. Hudome. “He talked about how grateful he was to have a second chance. It was inspiring.”

In 2016, Rep. Fitzpatrick underwent surgery after a cancer screening. His battle with cancer had continued in recent years, those who knew him said.

“Many don’t appreciate that he fought gravely for years dealing with the implications of his cancer," said former Rep. Pat Meehan, a Delaware County Republican who served in Congress with Rep. Fitzpatrick. “Throughout it, he was an outstanding representative who really knew his district and took a courageous and independent position on many issues.”

In Washington, Rep. Fitzpatrick focused on issues that included medical device safety, abortion, the banking reform debate, and end-of-life care. He also chaired a committee that developed legislation to address terrorism financing, pushed for cancer research funding, and advocated for victims of 9/11.

He was instrumental in opening the Washington Crossing National Cemetery for veterans in Upper Makefield Township. That was his “legacy issue,” Meehan said, “which will last in perpetuity.”

While he supported Republican priorities such as repealing the Affordable Care Act and lowering taxes and spending, Rep. Fitzpatrick often joined a small handful of more centrist House members in resisting the most far-reaching policies and confrontational tactics of the party’s ascendant right wing. He was also one of a handful of moderates who often broke with the party’s more conservative bloc to end repeated fiscal standoffs with the Obama administration, reopen the government after a shutdown in 2013, and provide an aid package after Hurricane Sandy.

The former congressman was the epitome of a northeastern Republican “back in the day,” said Hudome, the strategist.

“It’s a shame to see that strain of our party go the way of the past,” Hudome said. “There aren’t that many guys like Fitz in Congress. Moderate, easy to get along with.”

Hudome called Rep. Fitzpatrick “a solid guy,” “a classic Bucks County Irishman,” and “a family man first and foremost.” And he was a straight shooter, Hudome said: “You just knew exactly where he stood on things."

Murphy, who beat Rep. Fitzpatrick in 2006 and then lost the seat to him in 2010, said they “both tried to be gracious in victory and defeat.” He called Rep. Fitzpatrick “a tireless and tough campaigner.”

“Our nation lost a true patriot,” Murphy said. “Mike Fitzpatrick was a champion for our beloved Bucks County. No one worked harder than Mike.”

Rep. Fitzpatrick grew up in Levittown in a family of 10, graduating from Bishop Egan High School as an Eagle Scout. He attended St. Thomas University in Miami, and received a law degree from Dickinson School of Law.

He ran for the state House from Bucks County in 1990 and 1994, losing both times, and then became a county commissioner in 1995. He served for almost a decade before running for Congress. Rep. Fitzpatrick also practiced law with various firms in Bucks County.

“He exemplifies the kind of public servant that was in it for the right reasons,” Meehan said, “and in time, his legacy will be appreciated more and more.”

In addition to his brother, Rep. Fitzpatrick is survived by his wife, Kathleen, and their six children.

Plans for services had not been announced Monday.

Staff writer Jonathan Tamari contributed to this article.