Alabama Gov. Robert Bentley resigned Monday amid allegations he used state money to help cover up an affair with a top aide.

Bentley stepped down as part of a plea deal that saw him admit to two misdemeanor campaign and ethics charges. The 74-year-old grandfather of six was given a 30-day suspended jail sentence and a year of probation. The agreement includes provisions that Bentley not seek elected office again, that he repay campaign funds totaling $36,912 within a week and perform 100 hours of community service as a physician.

In a brief statement to his staffers, who applauded as he approached the microphones, Bentley said, "there have been times that I have let you and our people down, and I’m sorry for that."

"I can no longer allow my family and my dear friends … to be subjected to the consequences that my past actions have brought upon them," Bentley added.

Lieutenant Gov. Kay Ivey was sworn in later Monday, becoming just the second female governor in Alabama’s history.

"The Ivey administration will be open. It will be transparent. And it will be honest," she said.

Earlier Monday, state lawmakers began impeachment hearings against Bentley, one day after the Alabama Republican Party's steering committee passed a resolution calling on him to resign immediately.

Bentley had been under heavy political pressure since last year, when recordings surfaced of him making romantic and sexually charged comments in 2014 to aide Rebekah Caldwell Mason before his divorce.

Last week, state investigators released thousands of pages of documents and interviews, including multiple text messages that Bentley sent the aide, such as "I sure miss you. I need you. I want you. You are the only one."

The governor's then-wife, Dianne Bentley, was able to read the text messages because they also showed up on his state-issued iPad, which he had given the first lady. Dianne Bentley provided the messages to the committee.

The former first lady's chief of staff also told the committee's special counsel that Bentley threatened her job because he believed she had helped his wife make the recordings.

At one point, according to the 131-page investigative report, the governor sent the head of his security detail to fetch the recording from his son, Paul Bentley, who responded: "You ain't getting it."

Jack Sharman, special counsel to the state’s House Judiciary Committee, said Bentley “directed law enforcement to advance his personal interests and, in a process characterized by increasing obsession and paranoia, subjected career law enforcement officers to tasks intended to protect his reputation.”

He also said Bentley and his office “did not meaningfully cooperate” with the investigation.

Fox News.com's Barnini Chakraborty and The Associated Press contributed to this report.