Ruby Sycamore-Smith (21) won a reasonably comfortable victory over second-placed Zac Gawn. The voter turnout of 5193, or just over a quarter of students, was hailed as the best in a ''generation''.
Ms Sycamore-Smith, a marketing and communications student, said she was ''stoked'' to be elected president for next year.
She promised to fight hard before next year's general election on student issues, including tuition fee increases, student allowances and making sure students were ''supported for education''.
She would also consult students over whether they wanted OUSA and the university to be involved in running a pub.
Current president Francisco Hernandez did not run for a second term.
''This election has seen the highest number of votes cast in a generation, with 25% of the student members voting,'' Mr Hernandez said.
Ryan Edgar, the brother of former president Logan Edgar, was elected administrative vice-president.
OUSA executive election results.- President: Ruby Sycamore-Smith with 49.86% of the vote; administrative vice-president: Ryan Edgar, 47.55%; finance officer: Nick Tenci, 86.61%; education officer: Jordan Taylor, 51.82%, welfare officer: Nali Lee, 37.32%; postgraduate officer: Kurt Purdon, 82.49%; international students' officer: Kamil Saifuddin, 86.32%; campaigns officer: Hamish Barker, 43.20%; recreation officer: Henri Faulkner, 45.89%; colleges officer: Brydie Ockwell, 84.64%.
