ESL was founded more than 100 years ago by George Eastman, a prominent business leader and philanthropist of the twentieth century. Since then, ESL has grown to become a leading financial services organization in the Greater Rochester area.

ESL Federal Credit Union reaffirms its commitment to Greater Rochester 100 years after its founding on November 20, 1920. Founded by George Eastman as the Eastman Savings & Loan Association, the institution aimed to encourage thrift among Eastman Kodak employees to help them purchase homes and build community.

In 1995, ESL Federal Credit Union opened its first community branch in Irondequoit, marking a significant milestone in its expansion and service offerings.

On February 1, 1996, Eastman Savings and Loan Association transitioned from a U.S. bank to a Federal Credit Union, leading to the name change to ESL Federal Credit Union. This transformation marked a significant shift in the institution's structure and services.

In 1997, ESL Federal Credit Union established ESL Investment Services, LLC as a wholly owned subsidiary, expanding its range of financial services to include investment options.

ESL Investment Services, Inc. opens for business to provide members with retirement and wealth management products and services. It later became ESL Investment Services, LLC, in 2001.

ESL has been awarded the Democrat & Chronicle Rochester’s Choice Award in the Bank/Trust Company category every year since 2002, demonstrating the high regard and trust the members have for the institution.

In 2005, ESL documented its Core Values, outlining the guiding principles and beliefs of the organization.

The groundbreaking ceremony for ESL's new headquarters in downtown took place on July 30, 2008. The new headquarters, located at 225 Chestnut Street, was scheduled to be completed by 2010.

On April 17, 2009, it was mentioned that the ESL headquarters would be a positive addition to downtown, including the introduction of a drive-thru ATM. However, concerns were raised about the impact of an additional parking garage on ESL business.

In 2010, ESL Federal Credit Union inaugurated its new corporate headquarters in downtown Rochester, symbolizing its commitment to the local community and growth in the region.

On November 1, 2012, complaints were made about ESL's frequent changes to their BillPay interface, causing inconvenience to users who had just adapted to the previous changes.

In 2013, ESL established the VolunCare Program, allowing employees to volunteer for eight hours every year during work hours. The program led to over 500 ESL employees volunteering more than 3,000 hours in 2019 across 100 organizations.

In 2017, ESL Federal Credit Union established ESL Trust Services, LLC as a wholly owned subsidiary, further diversifying its financial services portfolio to include trust services.

Since 2018, ESL Federal Credit Union has been running its Community Impact initiative, reinvesting more than $100 million in grants throughout the community.

In 2019, ESL Federal Credit Union reinvested over $16 million in grants to nonprofits, showing a commitment to supporting the community and helping residents thrive financially.

On January 17, 2020, ESL distributed the largest Owners’ Dividend in its history, amounting to $20 million. This distribution marked a significant milestone as ESL had shared over $150 million with its members over the past 24 years.

ESL, the largest financial institution in Greater Rochester, celebrates its 100th anniversary by emphasizing its commitment to the community's growth and financial well-being.

A study conducted in 2021 to measure employee engagement globally, where 91% of employees at ESL Federal Credit Union rated it as a great place to work compared to 57% of employees at a typical U.S.-based company.

ESL Federal Credit Union's African American Women Employee Resource Group organized an event called 'Cultural Odyssey: Black History Exploration' in February to celebrate Black History Month in Rochester.

ESL Federal Credit Union released a financial snapshot showing their financial strength as of December 31, 2023. The snapshot includes details of their assets and liabilities.

In 2024, ESL Federal Credit Union employees in Rochester celebrated pride with various events and activities, including career Q&A nights, team-building volunteer activities, and a performance by the ESL House Band at the Annual Celebration.