A deep-pocketed nonprofit organization founded by the conservative activist Leonard A. Leo gave away $182.7 million in a year’s time, a new tax filing shows, demonstrating how aggressively it has worked behind the scenes to prop up other groups and causes on the right.

The organization, Marble Freedom Trust, was formed in 2020 and was funded by a gift of more than $1.6 billion — an extraordinary windfall that resulted from a single donor’s contribution of 100 percent of a company’s shares before the company was sold, leaving Marble with the proceeds of the sale, The New York Times reported last year.

Mr. Leo, a lawyer and former executive at the Federalist Society, has been instrumental in conservatives’ yearslong effort to push the federal judiciary to the right, both through his direct guidance to Republican leaders and by financing conservative causes. In recent years, he has built an opaque, far-reaching network of organizations — many of which have funding sources that are not required to be disclosed — that can influence elections and other matters, including education policy, abortion and campus free speech issues.

In a statement responding to questions about Marble’s work, Mr. Leo described it as an attempt to match Democratic efforts in the world of so-called dark money, a term used to describe the vast flow of funds — often from untraceable donors — through nonprofits and other organizations into politics and political causes. Democrats raised and spent more dark money for the 2020 election than Republicans did.

“It’s high time for the conservative movement to be among the ranks of George Soros, Hansjörg Wyss, Arabella Advisors and other left-wing philanthropists, going toe-to-toe in the fight to defend our Constitution and its ideals,” Mr. Leo said.

(Mr. Wyss, a Swiss billionaire, is a major donor to left-leaning nonprofit groups; Arabella Advisors is a for-profit consulting group that administers a network of progressive nonprofit organizations that together spent nearly $1.2 billion in 2020.)

Marble Freedom Trust, a tax-exempt 501(c)(4) “social welfare” organization, is a centerpiece of Mr. Leo’s network. The group’s stated mission is to “maintain and expand human freedom consistent with the values and ideals set forth in the Declaration of Independence and the Constitution.”

It was not immediately clear from the group’s record of contributions how Marble was realizing that mission. The recent filing for Marble — a tax record for the year ending on April 30, 2022, that was obtained by the liberal transparency group Accountable.US — does not reveal much about the ultimate destination of the $182.7 million.

In the year ending last April, according to the filing, Marble gave $153.8 million to the Schwab Charitable Fund, a manager of donor-advised funds, which allow people and entities to direct their deposits over time into charitable organizations, including some politically inclined groups and institutions.

Another $28.9 million went to the Concord Fund, a conservative advocacy organization. Formerly known as the Judicial Crisis Network, the group has acted as a funding hub in the past, giving tens of millions of dollars in grants to allied nonprofit groups and supporting in-house projects, including opposition to Democrats’ attempts to expand voting access.

From those two organizations, it is impossible to directly trace where the Marble money went.

During that approximate time period, according to Schwab’s tax filings, Schwab gave $141.5 million to another group linked to Mr. Leo, the 85 Fund — a nonprofit organization that says its mission is “to educate the public and support activities that highlight the relationship between structural limits on government power and the protection of our dignity and our freedom.”

The 85 Fund backs the Honest Elections Project, a conservative group founded in 2020 that has worked in states across the country to restrict voting access.

Some of the money that flows through Mr. Leo’s network of nonprofit groups goes to for-profit companies he controls. In 2021, the 85 Fund paid $21.75 million to CRC Advisors, a consulting firm run by Mr. Leo, according to the 85 Fund’s tax filings.

Several other entities in Mr. Leo’s network, including the Concord Fund, have also paid CRC Advisors millions of dollars in the last two years, tax records show.

“Marble Freedom Trust is Leonard Leo’s billion-dollar slush fund to erode democracy,” said Kyle Herrig, the president of Accountable.US. “With all this money under his control, Leo can push his extreme agenda by influencing conservative lawmakers on Capitol Hill, deploying state attorneys general to do his bidding and moving extreme bills in state legislatures.”

In a statement, Mr. Leo said that CRC Advisors “employs nearly 100 best-in-class professionals whose expertise goes across all aspects of public affairs, and we deliver results that are leading the conservative movement to win more than it has ever before.”

Marble’s grants last year declined slightly from the previous year, when the group reported nearly $229 million in grants, including to Concord and the 85 Fund.

Since the $1.6 billion windfall — which came from Barre Seid, an electronics manufacturing mogul — Marble has received no contributions or grants, but it did report $26.6 million in investment income last year. As of about a year ago, Marble still had $1.2 billion to spend.

Marble’s tax filing also shows that Mr. Leo’s salary for his part-time role at the company increased to $400,000 from $350,000.

Mr. Leo’s work, and his longtime relationship with Justice Clarence Thomas, have come under new scrutiny recently. The Washington Post reported last week that Mr. Leo had arranged for Justice Thomas’s wife, the conservative activist Ginni Thomas, to be paid tens of thousands of dollars for consulting work, and had urged to keep her name off the paperwork.

In a statement, Mr. Leo said the payment did not present a conflict of interest with the court. “It is no secret that Ginni Thomas has a long history of working on issues within the conservative movement,” he said. “The work she did here did not involve anything connected with either the court’s business or with other legal issues.”