Updated at 5 p.m. Tuesday with additional reaction and background

U.S. Rep. Jeb Hensarling won't run for re-election next year, a decision that continues the reshaping of Republican politics in North Texas.

The Dallas lawmaker joins Rep. Sam Johnson, R-Plano, as veteran GOP congressmen who are retiring at the end of 2018. It mirrors a trend across the country. According to CNN, at least 11 Republicans have announced they won't seek another term, resigned or are running for another office.

Hensarling, 60, has represented the 5th Congressional District since he was elected in November 2002. He chairs the powerful Financial Services Committee and has been a strong voice in regulating the financial industry.

"Today I am announcing that I will not seek reelection to the US Congress in 2018. Although service in Congress remains the greatest privilege of my life, I never intended to make it a lifetime commitment, and I have already stayed far longer than I had originally planned," Hensarling told supporters in a statement.

A staunch constitutional conservative, Hensarling has long believed that Congress was not a place for career politicians. Yet his announcement comes as a surprise to those who felt that he would be in line for more influential leadership posts.

In an interview with The Dallas Morning News, Hensarling said he was not seeking re-election because of the "oldest reason in the book:" family considerations. His children are teenagers and he wants to spend more time with them.

The Republican added that his term limit as chairman of the Financial Services Committee also provided a good departure point.

"I didn't come here to make elected office my lifetime avocation," he said. "I've got 14 more months and I've got a lot of work to do."

Hensarling said his decision was not influenced by the political climate in the GOP, where the rise of President Donald Trump has created friction and some division.

"Quite the opposite," he said. "I'm rather enjoying it."

The filing period for the March primary starts Nov. 11, leaving potential successors little time to make a decision and start the campaign process. District 5 includes the southeast portion of Dallas County including Mesquite and stretches southeast into Kaufman, Anderson, Henderson and Cherokee counties. The district is reliably Republican, with Trump winning 63 percent of the vote last November.

"Jeb is leaving Congress on his own terms, and his leadership will be greatly missed," said Kevin Brannon, a friend and political consultant who led Hensarling's first campaign for Congress. "He's admired and respected, and I believe he could have continued to serve for as long as he wanted."

Hensarling said Tuesday he would spend the rest of his term fighting for the conservative causes that drew him to politics.

"Although I will not be running for re-election, there are 14 months left in my congressional term to continue the fight for individual liberty, free enterprise and limited constitutional government — the causes for which I remain passionate," he said.

"Much work remains at the House Financial Services Committee in the areas of housing finance reform, regulatory relief, cybersecurity and capital formation to name just a few," he said. "Furthermore, important work remains in the Congress as a whole — especially pro-growth tax reform. I look forward to continuing this work on behalf of the people of the 5th District of Texas and all Americans."

Big loss for conservatives

Hensarling's colleagues in the House called him a model for conservatives.

"Throughout his time in Congress, Jeb has always been a conservative, principled leader," said Rep. Pete Sessions, R-Dallas. "I want to thank him for his service to our country, the Texas delegation, and to our conference as Financial Services Chairman. I am proud to call Jeb not only my colleague but my dear friend."

Texas Sen. John Cornyn said he was surprised by Hensarling's news, "but apparently others were not," he said.

"It will be a big loss," he said.

Texas Sen. Ted Cruz cringed when asked about Hensarling's decision, calling it "very disappointing news."

"Jeb is smart, principled, effective, he's done a terrific job in the House and he will be sorely missed," Cruz said.

House Speaker Paul Ryan said he would miss Hensarling's leadership.

"He is a true Constitutional Conservative who understands that free enterprise is critical to a thriving America," Ryan said in a prepared statement.

San Antonio Rep. Joaquin Castro, a Democrat, said he hadn't heard rumors that Hensarling was mulling the change, but noted that several high-profile Republicans, such as Tennessee Sen. Bob Corker, Arizona Sen. Jeff Flake and Reps. Ileana Ros-Lehtinen of Florida and Charlie Dent of Pennsylvania, have decided to not seek re-election in the age of Trump.

"The number of legislators, but especially Republicans, who have decided to leave the Congress this year is especially high compared to other years, and there have been a few surprises, just like Jeb's announcement today," Castro said.

Flake, who served with Hensarling for several years in the House, was stunned by the news.

Asked if he suspects that Hensarling is leaving for the same reasons Flake gave in announcing his retirement from Congress, Flake — who has lambasted Trump-ism and been skewered for his criticisms — chuckled.

"No, no ... He's very close to the speaker and that agenda," Flake said, referring to Ryan. "It's a big loss for the House, and the institution."

Potential replacements

Early speculation on who might seek to succeed Hensarling centered on some individuals with wealth — or high name recognition among conservative activists.

"Maybe one of the Huffineses will move there?" said GOP campaign consultant Jordan Berry, referring to Dallas businessmen and identical twins Don and Phillip Huffines.

Don Huffines is in the state Senate. Phillip, a former Dallas County GOP chairman, has announced for the Collin County-centered Senate seat being vacated by Van Taylor, who is the leading candidate to replace Johnson. In the race to succeed Taylor, Phillip Huffines faces Angela Paxton, wife of Texas Attorney General Ken Paxton — and Berry's client.

Retired Army Lt. Col. Allen West, who headed the Dallas-based National Center for Policy Analysis until it closed last summer, is a former Florida congressman and staunch conservative who has been mentioned as a possible successor to Hensarling.

The Texas Tribune reported that former Irving Mayor Beth Van Duyne, now regional administrator for the federal Department of Housing and Urban Development, may be interested.

In the Texas Legislature, Republican Sen. Bryan Hughes of Mineola is said to be interested. Though his only overlap with Hensarling's district is Wood County, north of Tyler, Hughes has served in Austin for 15 years. He enjoys ardent support from social conservatives and tea-party adherents.

In the Texas House, Reps. Cindy Burkett of Sunnyvale, Dan Flynn of Van and Lance Gooden of Terrell represent a portion of Hensarling's district.

Burkett, though, would have to give up her current primary challenge to state Sen. Bob Hall of Edgewood. While Hall lives in Hensarling's district, he's expected to focus on defending his Texas Senate seat.

Former Dallas GOP state Rep. Kenneth Sheets, when reached Tuesday, said he'd just learned of Hensarling's decision.

"I wouldn't have a comment," Sheets said, when asked if he's interested.

One Democrat, former Terrell City Council member Dan Wood, has announced his candidacy.

Rising star

Hensarling rose to rarefied heights in Washington, leading the powerful House Financial Services Committee and counting Vice President Mike Pence and Speaker Ryan as friends.

But he came from humble Texas roots: The son of a chicken farmer. Eagle Scout. Texas A&M Aggie.

Hensarling honed his political chops as a protégé of former U.S. Sen. Phil Gramm, a Texan known for his focus on financial issues. Before running for office, Hensarling was a top GOP strategist, serving as executive director at the party's Senate campaign arm when Gramm was chairman.

He rose quickly through the House, following the path of friend and future vice president Pence as chairman of the Republican Study Committee — an influential conservative bloc. That became a springboard to election as House Republican Conference chairman, the No. 4 leadership post, which he gave up after one term to take control of the powerful committee overseeing the banking industry. He toyed with a bid for speaker during the turmoil that followed John Boehner's ouster.

And if nothing else, Hensarling did Washington his own way.

He kept an unyielding focus on budget matters, displaying a live national debt clock in his committee's hearing room. And he earned a reputation for picking quixotic fights that on occasion rankled even his Republican allies.

Sometimes Hensarling won, helping to eliminate congressional earmarks, the line-item spending requests that he and others criticize as pork-barrel spending.

Sometimes he lost — and big. The Texan in recent years waged a high-profile battle to close the Export-Import Bank of the United States, calling it nothing more than corporate welfare. But his GOP colleagues eventually give him the work-around in a brutal, public fashion.

That dynamic has continued to the present term — and along with it criticism from Democrats that he is a rigid Wall Street shill who's not looking out for consumers.

Hensarling in June saw the House OK his rollback of far-reaching banking regulations created under President Barack Obama — but the Senate has not moved on the bill. He's also been unable to get much traction on his plans to overhaul a beleaguered flood insurance program.

But the Republican has almost reveled in taking on the odds.

"I'm not sure anything stays totally settled in this town," he said this summer.

Hensarling's future, however, has been a source of speculation for months. He was passed over to be Trump's Treasury secretary, a gig that ended up going to Steve Mnuchin.

Washington correspondents Tom Benning, Nicole Cobler, Todd J. Gillman and Katie Leslie and Austin correspondent Robert T. Garrett contributed to this report.