Rep. Kevin Brady (R-Tex.) said Thursday that he will seek the chairmanship of the powerful House Ways and Means Committee, jolting what many expected to be a smooth ascension to the post by Rep. Paul Ryan (R-Wis.), the former vice presidential nominee and the House GOP’s architect of fiscal policy.

Brady said in an interview that after months of mulling whether to run, he has formally decided to battle Ryan for the gavel. “Absolutely, I’m in,” Brady said. “I’m a proven leader on tax reform, trade, and health care. I’ve also spent a lot of time building respect, relationships, and trust, both on the committee and off, and I’m excited about the opportunity to lead and offer a choice.

“The members on the Ways and Means committee are extremely smart and engaged,” he added. “They know how important the next two to four years are for this committee.”

Brian Bolduc, a spokesman for Ryan, declined to comment on Brady’s candidacy. “Chairman Ryan is focused on his work at the House Budget Committee,” he said.

Ryan, who is considering a 2016 presidential bid, is widely seen as the stronger candidate for the position. But concerns about whether he would be fully committed to committee work as he simultaneously considers a bid for the White House have been voiced privately by some of his colleagues.

Enter Brady, 59, who said the chairmanship is his lone aspiration.

Calling his support “solid” and touting his “pro-family and pro-free enterprise” politics, Brady said he would not announce unless he thought he could win.

He acknowledged that Ryan, 44, is an exceedingly popular figure in the House Republican conference but said winning a committee race among a select group of members does not necessitate a national profile of similar stature.

In recent days, Brady said he shared his plans with Ryan and House Speaker John A. Boehner (R-Ohio) and assured them that it will be a “friendly race.” One of Brady’s roommates in his Capitol Hill apartment is Rep. Steve Scalise (R-La.), the House majority whip.

A House GOP leadership aide, who requested anonymity to speak freely, said Brady’s move disrupts what Ryan had thought would be a comfortable rise and forces the Wisconsin congressman to make a decision sooner rather than later on 2016.

Ryan, who chairs the House Budget Committee, has long been expected to lead the GOP’s legislative push next year to reform the U.S. tax code, and has been hinting at his playbook in interviews this month.

Brady said that he has raised more than $4 million ahead of the midterm elections, citing his combined fundraising for his political action committee, his House campaign, and the National Republican Congressional Committee. He called his haul a sign of his ability to raise money for committee members

“The expectations are very high for the next chairman, both on policy and on financial support for others,” Brady said. “I’m determined to exceed every one of those expectations.”

Ryan is one of the GOP’s most prolific fundraisers. He has millions in his campaign account and over the summer he donated more than $1 million to the NRCC. Brady said Thursday that he would match Ryan and committed to give $1 million to the NRCC as November’s elections neared.

Rep. Dave Camp (R-Mich.), the current Ways and Means chairman, will retire at the end of the session. In February, Camp released a comprehensive tax-reform proposal following years of work, including a cut of corporate tax rates and the elimination of several deductions, but it got little traction in the chamber.

“Chairman Camp has set the table beautifully,” Brady said. “I want to lead the House GOP’s positive reform agenda, from tax reform to key trade agreements and reforming the IRS.”

Brady, a former state lawmaker in Texas, has been moving closer to a run for chairman for much of this year, nurturing ties to grassroots activists and donors. His past clashes with Obama administration officials have drawn notice.

“Bottom line, I feel like I’m qualified and prepared to lead the committee, and at the right time I’m going to make that case to my colleagues,” he said, in a March interview with C-SPAN.