The Epsilon Zeta chapter was founded on May 11th, 1947 at 2:30 p.m. in the RPI Clubhouse (the present-day Lally Hall). As well as having national representatives on hand, five members of the RPI faculty and some Boy Scout executives attended. Russell Olsen was installed as president, Walter Locher as vice president, Peter Gundlefinger as secretary and John Thompson was installed as treasurer. There were forty charter members of the chapter, most of them veterans of World War II.

In the early years of the chapter, brothers spent a lot of time helping out at Vanderheyden Hall. The chapter donated money, built new facilities, painted and helped out in many other ways.

Services to the campus included the Lost and Found which was run out of the office in the RPI Clubhouse (now Lally Hall) beginning in 1947. Coat checks were run at school functions as well as manning concession stands at dances.

1949 saw the birth of the Used Book Exchange, which was initially run as a twice per semester event. Also in 1949 the chapter celebrated RPI's 125th anniversary by donating a Costa Blue Spruce tree to be used as a campus Christmas tree. (It was later cut down and replaced by a flag pole.)

The Meanest Man on Campus (MMOC) competition began in 1958. Faculty, staff and students all vied for the prestigious title. Members of the RPI community voted for their preferred contestant by donating money. All of the money raised was donated to a local charity. The very first MMOC winner was Captain Ray from ROTC.

The late 1960s saw some big changes for Epsilon Zeta as they moved from the Clubhouse to the newly constructed student Union building. EZ brothers helped with the dedication ceremonies for the new Union. That same weekend, EZ celebrated their 20th anniversary by hosting a banquet at Mario's in Troy.

A women's auxiliary was formed and Epsilon Zeta brothers invited the women to help with service projects. By 1976, women were allowed to become full members in Epsilon Zeta due to a change in Alpha Phi Omega's national bylaws.

Notable projects in the 1970s included building a ramp outside of the home of a 15-year-old cerebral palsy victim who could not walk, creating punch cards for the Folsom Library's books to help automate the circulation process and raising over $8,000 at a walk for the mentally handicapped.

The 1980s were spent fixing up the Approach, holding a Capital District Educational Fair and managing several successful Boy Scout camporees. In 1980 and 1984, the chapter was given the Arno Nowotny National Service Award. Also in 1984, Epsilon Zeta was granted the first ever Disborough Service to Scouting Award, also honored by the National fraternity.

The chapter continued to flourish in the 1990s. Red Cross blood drives, MMOC competitions, annual publication of the Infocard, and outstanding attendance at Sectional, Regional and National conferences. In 1998, Epsilon Zeta was recognized with an unprecedented third Nowotny Service Award.

In 2004, another Nowotny Service Award was received, making Epsilon Zeta the first chapter to receive four such awards. The chapter also received the Josiah Frank Historian's Award.

In 2010, Epsilon Zeta broke its own national record by being awarded its fifth Nowotny Service Award at the Atlanta, Georgia National Convention.

In 2018 our chapter started RPI Service Day to help students connect and bond with the local Troy community, this event has grown to be huge event in which RPI APO can contribute to reaching the goals of the Renssealer Forward Plan.

In 2023 our chapter recieved the Dean Arno Nowotny Service Award for an unprecedented and record breaking 6th time and Josiah Frank Historian Award for the 2nd time placing the chapter at 9 National Awards the most in the Nation.

Today, Epsilon Zeta continues to provide services to the campus, community and country. A scholarship program grants a $2,000+ award to incoming freshmen who demonstrate outstanding service and leadership skills. The chapter continues to innovate and provide beneficial services to students through the chapter office.