[14] On 31 January 2011, prior to that year's general election, MacSharry was appointed to the Fianna Fáil frontbench by the new party leader Micheál Martin, as spokesperson on Tourism and Arts.

[17][18] MacSharry authored a Fianna Fáil policy paper in February 2013 entitled, Actions Speak Louder than Words, which promoted the case for and approach to be taken for a reduction in loss of life through suicide by 30 percent.

[21] In 2020, MacSharry was re-elected in the same constituency, albeit with a reduced share of 7,004 votes (11.5%), being elected on the final count over his Fianna Fáil running mate Eamon Scanlon.

MacSharry caused controversy in 2020 when he accused public servants of "laziness" and said they were "using the COVID-19 crisis as an excuse to "lie on the couch and watch box sets".

[24][25] In January 2021, MacSharry attracted further controversy for his comments made during a Fianna Fáil parliamentary party meeting, in which he said that "if the Ku Klux Klan were selling a COVID-19 vaccine, Ireland should buy it".

He first called on Martin to resign in June 2021 after it had emerged Fianna Fáil had used covertly polled voters while pretending to be independent pollsters.

[30] MacSharry published a paper, Now More Than Ever in July 2021 on the impact of COVID-19 related restrictions on the mental health of society suggesting no further lockdowns should be considered.

[31] On 15 September 2021, MacSharry resigned from the Fianna Fáil parliamentary party in order to vote against Simon Coveney of Fine Gael in a motion of no confidence resulting from the Katherine Zappone controversy.