Charles H. Keating Jr., the financier at the center of the savings-and-loan crisis of the 1980s and 1990s. He served more than four years in prison and was charged with influence peddling with senators. He died March 31 at age 90. (Gary A. Cameron/The Washington Post)

Charles H. Keating Jr., a onetime lawyer and moral crusader who went to prison for fraud as the most prominent figure in the multibillion-dollar savings-and-loan scandal of the 1980s and 1990s, died March 31 in Phoenix. He was 90.

His longtime lawyer, Stephen Neal, confirmed the death to the Arizona Republic newspaper but did not disclose the cause.

Tall, intimidating and ever defiant, Mr. Keating was a onetime national swimming champion who led anti-pornography crusades since the 1950s. He later became a well-connected businessman who once flew Mother Teresa around the Southwest in his private helicopter.

Mr. Keating was also a flimflam artist who had reportedly been under federal investigation for financial malfeasance in the 1950s and again in the 1970s. In the 1990s, he was convicted of defrauding his company’s customers of millions of dollars in order to lead a life of baronial splendor.

In 1984, as deregulation swept through the banking industry, Mr. Keating borrowed $51 million to buy Lincoln Savings & Loan, a California-based thrift with 26 branches. It became a subsidiary of American Continental Corp., a Phoenix real estate development company controlled by Mr. Keating.

Lincoln Savings & Loan had about $1 billion in deposits when Mr. Keating took over the business. He pushed out the old executives and brought in friends and family in their places, paying his 28-year-old son a salary of $800,000.

Before his paper empire came tumbling down, costing taxpayers more than $3 billion, Mr. Keating was described in the Los Angeles Times in 1988 as “a businessman without apparent peer in Arizona in terms of riches, clout and color.”

He unabashedly used his political connections to keep federal regulators from looking too closely at his financial transactions. In 1985, Mr. Keating asked Alan Greenspan — later chairman of the Federal Reserve Board — to write a brief attesting to Mr. Keating’s conscientious stewardship of Lincoln.

He contributed heavily to congressional campaigns, including more than $1.3 million to five U.S. senators at the time: Alan Cranston (D-Calif.), Donald W. Riegle Jr. (D-Mich.), Dennis DeConcini (D-Ariz.), John Glenn (D-Ohio) and John McCain (R-Ariz.)

In 1987, the senators had a meeting with Edwin Gray, the head of the Federal Home Loan Bank Board, the agency that regulated savings and loans, asking him to go easy on Mr. Keating. Gray called the intervention by the so-called Keating Five “tantamount to an attempt to subvert the regulatory process.”

Later, when Mr. Keating was asked whether he expected favors from the public officials he supported, he replied, “I want to say in the most forceful way I can: I certainly hope so.”

Cranston was formally reprimanded by the Senate Ethics Committee, and Riegle and DeConcini­ were admonished for interfering with the Federal Home Loan Bank Board’s investigation. Glenn and McCain were absolved of any wrongdoing but were cited for “poor judgment.”

By law, no more than 10 percent of the money deposited in a savings and loan, according to federal law, could be invested in outside ventures. In 1986, a federal audit found that, under Mr. Keating’s control, Lincoln had greatly exceeded the federal limit on outside investment by some $600 million. His S&L customers — many of them retirees on fixed incomes — were steered toward investing their money in uninsured securities, or junk bonds.

Federal investigators accused Mr. Keating of running his businesses as a personal piggy bank, ransacking them for a series of risky investments. In three years — 1986 through 1988 — Mr. Keating paid himself and members of his family $34 million in salary, bonuses and stock. He had a helicopter and three corporate jets, including one with gold-plated­ bathroom fixtures.

He bought 20,000 acres in Arizona to build a city that was never completed. He used taxpayer money to build a lavish resort called the Phoenician, firing and hiring several designers for the project.

“It was a grotesque and audacious looting of Lincoln Savings & Loan,” Michael C. Manning, a Phoenix-based lawyer who handled many of the civil lawsuits against Mr. Keating, said Wednesday in an interview. “He made extraordinarily risky investments with taxpayer dollars.”

In a report to the Federal Home Loan Bank Board, the accounting firm investigation of Mr. Keating noted, “Seldom in our experience as accountants have we experienced a more egregious example of the misapplication of generally accepted accounting principles.”

In April 1989, regulators from the Federal Deposit Insurance Corp. raided Lincoln Savings & Loan, which went into bankruptcy, along with its parent company.

During a four-month trial in a California state court in 1991, Mr. Keating maintained that he was an innocent victim of vengeful government prosecutors.

An elderly woman grabbed his lapels and screamed at him to return her money. In a hallway outside the courtroom, another angry investor slapped him in the face with a wig.

The prosecution brought 53 witnesses to testify against Mr. Keating. The defense rested without calling a single witness. He was convicted on 17 of 18 counts of fraud and sentenced to 10 years in prison.

Two years later, Mr. Keating and his son, Charles Keating III, were convicted on federal charges of racketeering, fraud, conspiracy and transporting stolen property. He was sentenced to 12 years, to run concurrently with his other prison term.

He had served less than five years when both convictions were overturned on technicalities. In 1999, the 75-year-old Mr. Keating pleaded guilty to bankruptcy fraud but was spared from returning to prison. Charges against his son were dropped.

Charles Humphrey Keating Jr. was born Dec. 4, 1923, in Cincinnati. His father was a dairy-company­ executive.

Trained as a Navy fighter pilot during World War II, Mr. Keating did not serve in combat. The 6-foot-5 Mr. Keating was a national champion swimmer at the University of Cincinnati, from which he received a law degree in 1948.

He married Mary Elaine Fette in 1949 and had six children. His son and a son-in-law, Gary Hall Sr., were Olympic swimmers. A grandson, Gary Hall Jr., won 10 medals, including five gold medals, in Olympic swimming events. A complete list of survivors could not be confirmed.

Mr. Keating practiced law in Cincinnati with his brother, William Keating, who served in Congress from Ohio in the 1970s. One of the brothers’ law clients was Carl H. Lindner Jr., a Cincinnati tycoon who hired Charles Keating as an executive of one of his companies, American Financial Corp., in 1972. Mr. Keating settled in Arizona in 1976.

In the late 1980s, when Mr. Keating was still flying high, he took family members on a three-week tour of the finest hotels in Europe, which he wrote off as a business expense.

After federal authorities seized his companies, Mr. Keating told Time magazine in 1990, “My family and I probably have no net worth. Period. We’re broke.”