Unhappy with the results of his $125 million investment in Jewish causes over the past 12 years, philanthropic trailblazer Michael Steinhardt says that he is scaling back and refocusing the efforts of his signature foundation, Jewish Life Network/Steinhardt Foundation.

“I felt that some of the places I spent money were not where I really wanted to be spending money, that I knew were not achieving what I wanted to achieve and they created conflicts for me and difficulty for me, and I think that period is over,” Steinhardt said last week in his Manhattan offices.

In recent months, according to sources close to him, Steinhardt — who is well known for acerbic comments and ruffling feathers — had become increasingly pessimistic about the Jewish world and the impact of his investments. He articulated this disappointment publicly in May at a banquet for Hillel: The Foundation for Jewish Campus Life.

“I ask myself, overall, is the Jewish world any better today than it was 13 years ago? Have things really improved, are we reaching more people?”

“I don’t have positive answers,” he continued. “Outside of our self-congratulatory bubbles, things haven’t changed much.”

Steinhardt — who is perhaps best known as a founding partner of birthright Israel, a program that provides free trips to Israel for college students — said he will honor his previous financial commitments and maintain some level of support for many of the causes that his foundations currently fund.

In the future, however, he wants to focus on crafting what he calls a “common Judaism” and developing programs that speak to the unaffiliated, as opposed to those who are already in some way connected to Judaism.

He said he will narrow his attention to three major areas: creating follow-up programs for birthright participants after they return home; building a $100 million Fund for the Jewish Future, also known as Areivim, to transform formal and informal Jewish education, and the Jewish Early Childhood Education Initiative.

He will end his financial support for at least 18 of the 100 or so initiatives he funds, but opted not to discuss specifics. Her also will be stepping down as chairman of the day-school initiative, the Partnership for Jewish Education, but he will continue his commitment of $1.5 million over five years.

“The last six months have been particularly hard because I came to the realization that I was doing things I really did not want to be doing, that were really not where my head was,” Steinhardt said

In the wake of the shift, Rabbi Irving “Yitz” Greenberg stepped down as the Jewish Life Network’s top professional, a post from which he had served as Steinhardt’s top adviser on Jewish initiatives since the organization’s founding in 1995.

The departure marked the end of a prominent and ideologically improbable partnership between Steinhardt, a self-described atheist, and Greenberg, an Orthodox theologian.

In recent months, the overall staff at the Jewish Life Network has been reduced from 12 to seven, according to sources at the organization. Rabbi David Gedzelman remains its executive director.

Steinhardt has tapped the CEO of the Jewish Federation of Metropolitan Detroit, Robert Aronson, to head the $100 million Areivim fund.

“I think Michael is taking a whole new look at JLN,” Aronson said. “It is a very good idea. I think it will energize him. He has had a tremendous impact on American Jewish philanthropy, through his ideas and initiatives.”