Gerry Adams stepped down after being the leader of Sinn Féin since 1983, on Saturday afternoon.
Around 1,500 people gathered for the meeting in the Dublin's RDS, following a statement of Friday night from Adams in which he said that he believes that a way forward can be found to restore the power-sharing executive at Stormont.
McDonald was the sole candidate for the position, while Michelle O’Neill has formally been elected as Vice President of the party at the Ard Fheis.
According to the RTE, there was also huge applause when MEP Martina Anderson praised the contribution of Gerry Adams to both the party & the peace process.
McDonald said that she believes the party is ready for Government in both the North and the South and told delegates that she expects the talks about restoring the power-sharing institutions to conclude next week.