Dennis Hastert, the longest-serving Republican US House speaker, died over the weekend, a coroner said on Monday. He was 84.

Hastert, who was speaker from 1999 until 2007, died of natural causes at his home, according to Jacquie Purcell, the Kendall county coroner.

When he was sentenced in 2016 to more than a year behind bars, the former history teacher became one of the highest-ranking US politicians ever ordered to prison.

He had also helped turn much of George W Bush’s presidential agenda into law before his own political legacy was forever fouled by allegations that he molested high school athletes when he was a wrestling coach,

In the late 1990s, Hastert was a little-known Illinois lawmaker with a reputation for congeniality that had helped him ascend the ranks of congressional leaders. Republicans elected Hastert to succeed Newt Gingrich after the latter lost support because of ethics violations and their party’s showing in an election. In his first weeks on the job, he presided over the US House while the Senate conducted Bill Clinton’s impeachment trial.

After the Republicans reclaimed the White House, Hastert took much of what Bush proposed and steered it to passage, including large tax cuts and a measure that amounted to a huge expansion of prescription drug benefits – the biggest change in Medicare in decades.

His legacy was suddenly thrown into doubt in 2015, when he was accused of evading banking regulations as part of a plan to pay hush money to conceal unspecified “prior misconduct”. Nearly a year later, prosecutors filed papers that described what media reports had suggested for months: Hastert’s misconduct involved the sexual abuse of teenage boys on his wrestling team in the small town of Yorkville, west of Chicago.

During a 16-year coaching career, he led his team to a state championship and was named national coach of the year in 1976. But behind the accolades, prosecutors said, Hastert sexually abused at least four team members from 1965 to 1981.

The person Hastert was paying, identified in court papers only as Individual A, said the abuse occurred in a motel room when he was 14 on the way home from wrestling camp. Hastert allegedly touched other wrestlers in a locker room after saying he would give them massages. Two wrestlers said Hastert performed sex acts on them.

Prosecutors also described a recliner where Hastert often sat in the locker room with a direct view of the stalls where the boys showered.

Hastert agreed to plead guilty to evading banking laws. In all, he paid more than $1.7m out of $3.5m that he had promised to Individual A, sometimes in lump sums of $100,000 cash.

At the sentencing hearing where he received 15 months behind bars, the visibly angry judge called Hastert a “serial child molester”. A former wrestler struggled with his emotions as he told the court about his “dark secret” from adolescence.

Hastert, in his own statement, said he was “deeply ashamed” and admitted that he “mistreated” some of his athletes. But he never referred directly to sexual abuse.

The public knew nothing about Hastert’s past when Republicans lost seats in the 1998 midterm elections. Hastert confronted Gingrich about dissatisfaction in the Republican ranks, saying it was unlikely Gingrich could hold his post, Hastert wrote in his memoir Speaker: Lessons from 40 Years in Coaching and Politics.

“Well, I’ll make them support me,” he quoted Gingrich saying of the Republican rebels.

Told that was unlikely, Gingrich asked Hastert what to do.

“Do what you have to do,” he replied. The next day, Gingrich stepped down as speaker and left the House.

Hastert’s path to the speaker’s office was cleared when Bob Livingston, a Louisiana congressman who was considered a lock to replace Gingrich as speaker, resigned after acknowledging several extramarital affairs.

Hastert lived his entire life in Chicago’s suburbs, primarily in the Yorkville area. While growing up, he helped his father with the family feed business.

Survivors include his wife, Jean, and two adult sons.