The Union's ultimate governing body is its Annual Congress, and its executive authority is vested in a its National Council, comprising representatives from each member organisation.

It is convened, on monthly to six-weekly basis, to direct the overall work of the national union, amend the schedules to the constitution and determine interim policies responsive to events.

[citation needed] Chief Justice John L. Murray was USI president in 1966/67 and broadcaster Joe Duffy held the post in 1983–84.

Political strategist Frank Flannery, Cambridge University and Yale Professor Denys Turner and barristers Karen Quinliven QC, Grainne McMorrow SC and Giollaiosa O Lideadha SC all served as president, while SDLP Leader Mark Durkan was Deputy President and Minister of State at the Department of Health Alex White TD served on the USI officer board.

Jemma Dolan, Sinn Féin MLA for Fermanagh and South Tyrone was vice president for Campaigns and Communications for the University of Ulster Students Union.

[10] Political activist and victim of the miscarriage of justice after the Sallins Train Robbery, Osgur Breatnach, was a member of the Students' Representative Council of UCDSU.

[11] Irish Ambassador to the United Kingdom Dan Mulhall was deputy president of the Students Union in University College Cork.

[17] Eugene Murray, editor of Today Tonight and later head of TV Current Affairs with RTÉ was President of TCD SU in 1971.

[18] In 2020 the deputy president of the USI Michelle Byrne resigned following undercover reporting by a right wing student publication 'The Burkean'.