CAIRO—Moaz Abdel Karim, an affable 29-year-old who was among a handful of young activists who plotted the recent protests here, is the newest face of the Muslim Brotherhood. His political views on women’s rights, religious freedom and political pluralism mesh with Western democratic values. He is focused on the fight for democracy and human rights in Egypt.

A different face of the Brotherhood is that of Mohamed Badi, 66-year-old veterinarian from the Brotherhood’s conservative wing who has been the group’s Supreme Guide since last January. He recently pledged the Brotherhood would “continue to raise the banner of jihad” against the Jews, which he called the group’s “first and foremost enemies.” He has railed against American imperialism, and calls for the establishment of an Islamic state.

After Egyptian President Hosni Mubarak stepped down on Friday amid the region’s most dramatic grassroots uprising since the Iranian Revolution in 1979, the Brotherhood became poised to assume a growing role in the country’s political life. The question for many is: Which Brotherhood?

It was Mr. Karim and his younger, more tolerant cohorts who played a key role organizing the protests that began on Jan. 25 and ultimately unseated a 29-year president. But it’s the more conservative, anti-Western old guard that still make up by far the bulk of the group’s leadership.

Mr. Badi, the current leader, wrote an article in September on the group’s website in which he said of the U.S. that “a nation that does not champion moral and human values cannot lead humanity, and its wealth will not avail it once Allah has had His say.”

He wrote in that same article that “resistance is the only solution against the Zio-American arrogance and tyranny, and all we need is for the Arab and Muslim peoples to stand behind it and support it… We say to our brothers the mujahideen in Gaza: be patient, persist in [your jihad], and know that Allah is with you…”

On Monday, meanwhile, Mr. Karim stood shoulder to shoulder at a press conference with youth leaders from half a dozen mostly secular movements, to lay out their vision for how Egypt’s transition to democracy should proceed and to praise the Army for cooperating. Their top demand: a unity government that includes a broad swath of opposition forces.

he Brotherhood, whose leaders Mr. Karim butted heads with in recent weeks, put out a similar message on Saturday calling for free and fair elections. Seeking to allay fears that it would make a power grab, the Brotherhood also said it wouldn’t run a candidate in presidential elections or seek a majority in parliament.

Both Egyptians and outsiders, however, remain wary. They are unsure about how the group will ultimately harness any newfound political gains and whether its more-moderate wing will, in fact, have lasting clout.

“It’s never entirely clear with the Brothers,” says Josh Stacher, a political science professor at Kent State University who spent years in Egypt studying the organization. “It’s a big group, with lots of different points of view. You can find the guy always screaming about Israel and then you got the other guys who don’t care about Israel because they’re too busy worrying about raising literacy rates.”

Israel, which shares a long and porous border with Egypt, fears that if a moderate wing of the Brotherhood exists—and many in Israel’s leadership are skeptical that it does—it could be shoved aside by more extreme factions within the group.

The Brotherhood’s conservative wing has for years put out anti-Israel comments and writings, and helped fund Hamas, the Palestinian militant group. It has also spoken out in support of attacks against U.S. soldiers in Iraq and Afghanistan.

“If the Muslim Brotherhood comes to power, through elections or some other way, that would be a repeat of 1979 in Iran,” when moderate governments installed after the shah gave way to the ayatollahs, says a senior Israeli official. “It’s something we’re looking at with great caution.”

The U.S. appears to be taking a wait-and-see approach, with officials saying in recent days it should be given a chance. President Barack Obama, in an interview with Fox News, acknowledged the group’s anti-American strains, but said it didn’t enjoy majority support in Egypt and should be included in the political process. “It’s important for us not to say that our only two options are either the Muslim Brotherhood or a suppressed Egyptian people,” he said.

The outlawed Islamist opposition group is plagued by rifts between young and old, reformist and hard-liner. There are big city deal-making politicians, and conservative rural preachers who eschew politics in favor of proselytizing Islam.

Egypt’s government has long highlighted the group’s hard-line wing as a threat to the country. Yet its selective crackdowns have historically empowered the very hard-liners it has sought to undermine, analysts and Brotherhood members say.

The conservative leadership’s autocratic leadership style within the movement, its lack of tolerance for dissenting opinions and its preference to conduct business behind closed doors have all contributed to deep skepticism among outsiders about the Brotherhood leadership’s stated commitment to democracy.

In recent years, meanwhile, the group’s pragmatic wing has forged a historic alliance with secular opposition activists. Their role in the unseating of Mr. Mubarak appears to have given them a boost in a struggle for influence with the Brotherhood’s fiery old guard.

“The Muslim Brotherhood as a whole doesn’t deserve credit for this revolution, but certain factions within the movement absolutely do, generally those that have more modern views,” says Essam Sultan, a former member of the group who left in the 1990s to form the moderate Islamist Wasat, or Centrist, Party. “That wing should get a massive bounce out of this.”

Whether that bounce will be enough to propel the more-moderate Brothers to a permanent position of influence—or what their legislative agenda would actually be—is one of the key unknowns in Egypt’s political evolution.

In many ways, this faction resembles conservative right-of-center politicians elsewhere in the Arab world. They espouse a view of Islam as a part of Egyptian heritage and argue that democracy and pluralism are central Islamic values. They are pious and socially conservative, and reject the strict secularism that is a feature of most Western concepts of liberal democracy.

On Wednesday, when it was still unclear whether Mr. Mubarak would step down, Essam el-Eryan, one of the only reformists currently on the group’s 12-member ruling Guidance Council, said in a statement that the group didn’t seek the establishment of an Islamic state; believed in full equality for women and Christians; and wouldn’t attempt to abrogate the Camp David peace treaty with Israel—all tenets espoused by Brotherhood leaders over the decades. Mr. el-Eryan said those Brothers who had suggested otherwise in their writings and public comments in recent days and years had been misunderstood or weren’t speaking for the organization.

Founded in the Suez Canal town of Ismailiya in 1928 by a 22-year-old school teacher, the organization used violence to battle the British occupation in the 1940s.

The group allied with some young officers to overthrow the king in 1952 and bring Gamal Abdel Nasser to power, only to become implicated in an assassination attempt on Nasser two years later. He responded with a fierce crackdown, sending the group’s leadership to prison for years, and its membership ranks into exile.

The Muslim Brotherhood abandoned violence in the years that followed, formally renouncing it as a domestic strategy in 1972. But some of its offspring have taken a bloodier path. Some former members established the group responsible for the assassination of Egyptian President Anwar Al-Sadat in 1981, and others have allied with Al Qaeda.

In the late 1970s and early 1980s, an older generation of leftist and Islamist student activists battled each other violently on college campuses. Egypt’s opposition grew increasingly ineffective, partially as a result of those rifts.

“We saw three successive generations of Brotherhood leaders fail to bring change, and we learned from their mistakes,” says Mr. Karim, one of the leaders of the group’s youth wing.

Brotherhood and secular leaders say the seeds of the cooperation that drove this year’s protests were planted in the early 2000s when Israel’s crackdown on the second Palestinian uprising and the 2003 U.S. invasion of Iraq brought secularists and Islamists alike into the streets to protest a common cause.

Then, in 2005, the Brotherhood struck a key victory in the parliamentary elections, winning an all-time high of 88 seats. Though officially banned, the organization is tolerated and allowed to put up candidates as independents.

Many of the Brotherhood lawmakers were pragmatists compared to the hard-line members of the group who preferred to stay out of politics. They were more open to working with other groups to forge compromises, and won plaudits from secular opposition leaders by focusing their legislative efforts on fighting an extension of the country’s emergency law.

They also stood up for the independence of the judiciary and pushed for press freedoms, and didn’t work to ban books or impose Islamic dress on women—moves many critics had feared.

“In the past, Muslim Brothers in parliament sometimes made noise about racy books or the Ms. Egypt beauty pageant, and it made a lot of us uncomfortable,” says Osama Ghazali Harb, head of the National Democratic Front, a secular opposition party. “They didn’t do this in the last five years.”

The regime responded to the Brothers’ newfound parliamentary prowess with one of the most brutal crackdowns in the group’s history. Instead of coming down on the organization’s hard-line leaders, it focused on the movement’s moderates.

“The government wants them to be secretive, hard-line, because it makes them fulfill the role of the bogey man that they’re propped up to be,” says Kent State’s Mr. Stacher. “You don’t want soft and squishy huggable Islamists, and you don’t want sympathetic characters. You want scary people who go on CNN and rail against Israel.”

Eighteen Brotherhood legislative staffers drafting education and health-care reform bills were among hundreds arrested. So, too, were the leading pragmatists on the movement’s 12-man leadership bureau.

The power vacuum was quickly filled by conservatives, who in 2007 put out a platform paper walking back many of the group’s more-moderate views.

It stated, for example, that neither women nor Christians were qualified to run for president. Casting further doubts on the organization’s commitment to the separation of church and state, the paper called for a religious council to sign off on laws.

Rifts between conservatives and reformers in the group began to flare into the open. The group’s moderates argued that the paper was only a draft and never officially adopted.

In the 2008 elections to the Brotherhood’s Guidance Council, hard-liners nearly swept the field, according to people familiar with the group. Only one seat on the leadership council is held by a consistent reformist, say these people, as well as one of the two alternate members who would step in should someone be arrested or die.

During this same period, Mr. Karim, from the Brotherhood’s youth wing, says his relationships with activists in other groups were being cemented through online networks. “The new media allowed me to connect with the other” activists in Egypt, he says. “And I realized that there are things we agree on, like human-rights issues and political issues.”

Past partnerships between the Brotherhood and secular parties had been top-down short-lived agreements born of political necessity.

This latest alliance formed more organically, say several young activists who are working with the Brotherhood.

“We just got to know, trust and like each other, even—believe it or not—the Brothers,” says Basim Kamel, a 41-year-old leader in Mohamed ElBaradei’s secular movement.

As conservatives were gaining influence within the Muslim Brotherhood’s leadership ranks, Mr. Karim and his fellow youth cadres were growing impatient.

He says they began arguing with their superiors, saying the group was losing credibility in the street because they weren’t out protesting for democracy like the secular activists were.

In November 2008, the Brotherhood’s then-leader Mahdy Akef called for “establishing a coalition among all political powers and civil society” to challenge the “tyranny that Egypt is currently witnessing.”

Mr. Akef couldn’t be reached for comment, but those familiar with the group’s inner workings say the shift came as the leadership realized they risked losing their youth cadres, particularly after a series of high-profile defections by young Brotherhood activists.

When Mr. ElBaradei returned to Egypt in February 2010 to lead an alliance of opposition groups, many of them youth-driven, the Muslim Brotherhood backed him, formalizing a partnership that had already gelled among the rank and file.

The alliance was uneasy at times. When other opposition groups voted to boycott November’s parliamentary elections, for example, the Brotherhood broke ranks and ran.

After the uprising in Tunisia in January, Brotherhood youth, including Mr. Karim, met with the leaders of other youth movements and decided to plan a similar uprising in Egypt.

A group of about 12 youth leaders, including Mr. Karim, met secretly over the course of two weeks to figure out how to plot a demonstration that would outfox security forces.

The Brotherhood’s senior leadership refused to endorse their efforts at first. They ultimately agreed to allow members to participate as individuals—and to forgo holding up religious slogans that the Brotherhood might have used in the past, such as “Islam is the solution,” or waving Korans.