Her early interest in court proceedings was increased by hearing stories about her grandfather, a sharecropper and pastor, who in the 1930s had helped people move to the north to escape racial persecution under the Jim Crow laws of the time.

She remained there until January 20, 2010, when President Barack Obama nominated Lynch to again serve as United States attorney for the Eastern District of New York.

[16][17] Lynch's office prosecuted Republican congressman Michael Grimm; prosecuted Democratic politicians Pedro Espada Jr. and William Boyland, Jr.; investigated Citigroup over mortgage securities sold by the bank, resulting in a US$7 billion settlement; and was involved in the US$1.2 billion settlement with HSBC over violations of the Bank Secrecy Act.

The investigation culminated in the indictment of 14 senior FIFA officials and sports marketing executives shortly after Lynch was confirmed as Attorney General.

Replacing Lynch, Robert Capers was confirmed by the U.S. Senate as U.S. Attorney for the Eastern District of New York on December 15, 2015, taking his oath of office on January 4, 2016.

She became a partner in the firm's litigation department, where she represents individuals, companies, and corporate boards of directors in high-stakes cases, regulatory matters, and investigations.

[26][27] On November 8, 2014, President Barack Obama nominated Lynch for the position of U.S. attorney general, to succeed Eric Holder, who had previously announced his resignation, pending confirmation of his replacement.

[38] On March 3, 2016, following the occupation of the Malheur National Wildlife Refuge, Lynch said charges would be filed soon against participants in the standoff while appearing in Portland, Oregon, to commemorate the community's policing.

[40] In April 2016, Lynch took an active role in addressing what she called the difficulty of re-entry into society by felons, writing an op-ed[41] and making public appearances in support of raising awareness.

In June 2016, in response to the Orlando nightclub shooting, Lynch made multiple appearances on television news shows to highlight the ongoing investigation of the FBI.

[46] The local FBI agents and federal prosecutors had determined that charges should not be brought in the case, prompting strong disagreement from attorneys in the Washington, D.C. office of the Department's Civil Rights Division.

[46] In early March 2016, the FBI reportedly received a highly classified Russian government document earlier obtained by hackers working with Dutch intelligence.

The document, which was considered genuine but had "possible translation issues", had purportedly contained a memorialization of an email sent by Debbie Wasserman-Schultz to Leonard Benardo that had allegedly referenced a conversation between Lynch and Amanda Renteria.

[58] The next day, during a press conference in Phoenix, Lynch denied the conversation was about the Hillary Clinton email controversy or any matters pertaining to it, saying the discussion instead involved personal social topics such as travels, golf, and grandchildren.

[59] On July 1, 2016, Lynch swore she would "fully accept" the recommendation of the FBI and prosecutors regarding the email probe, and admitted that she understood how the meeting was raising "questions and concerns", and that she "certainly wouldn't do it again".

In his closely watched Senate Intelligence Committee testimony, otherwise devoted to discussing the circumstances of his firing, Comey said that tarmac meeting was a "deciding factor" in his decision to act alone to update the public on the Clinton probe—and protect the Bureau's reputation.

[68] The Inspector General's report, released in June 2018, called Lynch's tarmac meeting with Bill Clinton an error of judgment for the public perception it created, but found no political bias.