Just when Casada will meet with legislative leaders to finalize his exit isn't known. It's also unclear who will replace him, or how, in a chamber that currently has a Republican supermajority.
"When I return to town on June 3, I will meet with caucus leadership to determine the best date for me to resign as speaker so that I can help facilitate a smooth transition," Casada said in a statement.
Casada finally conceded after Gov. Bill Lee issued a stern warning that he would call a special legislative session following a 45-24 secret ballot vote in the GOP caucus declaring that his fellow Republicans no longer have confidence in Casada's ability to lead.
"Speaker Casada has made the right decision, and I look forward to working with the legislature to get back to conducting the people's business and focusing on the issues that matter most to our state," Lee, who was newly elected as governor in November, said in a statement on Tuesday.
Casada had been dogged by calls to resign since it was revealed he exchanged text messages containing sexually explicit language about women with his former chief of staff several years ago, among other controversies.
Rep. Patsy Hazelwood, a Republican from Signal Mountain, was one of the first GOP members to support Casada stepping aside as a "good first step."
"As a caucus, we need to take whatever additional steps are necessary to root out this type of behavior and to make sure there is zero tolerance for demeaning and denigration of any gender or ethnicity in the people's House," she said in her statement.
Just seven of the House's 73 Republicans are women.
Lawmakers were still trying to figure out Tuesday if the governor would have to call them back to the Statehouse to replace Casada, or wait until January when the General Assembly is scheduled to be back in town.
That's because the move to remove a House speaker is largely unprecedented in Tennessee's modern political era. The last Senate speaker resignation came in 1931. And in 1893, a House speaker declined to resign and his office was declared vacant, according to legislative librarian Eddie Weeks.
Speaker Pro Tempore Bill Dunn - who would immediately take over the top seat in the interim - told news outlets that he's "willing" to serve as speaker should the House elect him. However, a handful of leading lawmakers are expected to also angle for the top seat over the next few weeks.
Separately, GOP Rep. Mike Carter, who originally raised concerns about Casada's ethics panel involvement , told the Chattanooga Times Free Press he was asking staffers to prepare a petition calling for a full removal of Casada from office.
Casada's resignation announcement marked a quick, turbulent downfall for the Franklin lawmaker, who has spent only a few months in the House's top position.
Casada stepped into his role as speaker in January, after serving as majority leader. Bouncing back from a failed bid for speaker more than eight years beforehand, he received 47 secret ballot votes out of 73 Republicans in the 99-member chamber to become speaker-elect in November, defeating Reps. Curtis Johnson of Clarksville and David Hawk of Greeneville.
Casada built up political capital by spending heavily on Republican candidates in last year's elections, including contested primaries for open Republican seats. He also backed Republican Rep. David Byrd, whom three women have accused of sexual misconduct when he was their high school basketball coach several decades ago.
Casada released digital ads comparing the scrutiny Byrd was under to that given to U.S. Supreme Court nominee Brett Kavanaugh and President Donald Trump.
Byrd was then among more than 40 Republicans whom Casada rewarded with chairmanships of the committee and subcommittee system he expanded. Casada removed Byrd from the post near the end of the last legislative session after protesters showed up at his education subcommittee's meeting for months.
His political support began to waver when his former chief of staff, Cade Cothren, was pressured into resigning after the release of years-old racist texts and the sexually explicit messages, and Cothren's admission that he used cocaine in his legislative office years before becoming Casada's top aide. Casada was included in one of the group texts with a racist message, but has said he never saw it.
Another scandal that sparked early doubts was the report of possible evidence tampering by Cothren with a young black activist's criminal case, which a special prosecutor is still investigating. Casada denied that tampering allegation and a variety of others that continued to pile up, ranging from accusations that he spied on legislative members to a GOP colleague's claim that Casada tried to "rig and predetermine" an ethics review regarding his controversies.
Copyright 2019 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.