During his tenure as assistant CEO of the Louth Country Enterprise Board (1995–2000), Gallagher studied for a Diploma in Management in the Dundalk Institute of Technology from 1997 to 1999, after which he completed an MBA in 2000 at the University of Ulster.

It is not clear whether these roles are full-time or part-time, and the non-public service activities he was engaged in (e.g. he is recorded as stating that he was a fitness instructor and massage therapist in the 1990s[4][8]).

[d][9][10] After O'Hanlon lost his cabinet minister position when Albert Reynolds came to power in Fianna Fáil in 1992, Gallagher said that he was an Enterprise Officer for the Blanchardstown Area Development Partnership from 1993 to 1995.

In June 2000, Gallagher, aged 38, left the Louth County Enterprise Board ("LCEB") to set up a company called Home Wiring Systems Limited ("HWSL") with electrical tool-maker, Derek Roddy.

[16] In December 2006, the then Fianna Fáil Taoiseach Bertie Ahern opened their new offices, at which Gallagher announced he planned to invest €10 million and create 100 jobs.

[20] In January 2010, after Gallagher was elected to the Fianna Fáil National Executive in 2009, Mary Coughlan appointed him to the Board of FÁS, until 2012.

[21] In June 2010, Gallagher was also appointed by Fianna Fáil Minister for Transport, Noel Dempsey, to be Chair of the Drogheda Port Company, which he held until 2012.

In October 2011, Gallagher said of his time with O'Hanlon: "I had a network of contacts built up within departments so good that other ministers would ring me to get things done.

[33] In June 2006, Gallagher, while still CEO of SmartHomes, became Director of Elections for Fianna Fáil Louth TD and parliamentary party chairman, Séamus Kirk, whose seat was under threat from Sinn Féin.

[32][4] In the May 2007 general election, Kirk was successfully re-elected and topped the poll, even beating his fellow Fianna Fáil running mate, the then Minister for Justice, Dermot Ahern.

[4][34] In July 2008, Gallagher hosted a €5,000 per-head fund-raising dinner for 40 people in the Crowne Plaza Hotel in Dundalk, County Louth, for the new Taoiseach, Brian Cowen.

[38] In June 2011, it was reported Gallagher approached Fianna Fáil Oireachtas members to run as an Independent candidate, but with a "semi-detached" relationship to the party.

[43] On 25 September 2011, the first of six major RED C and MRBI opinion polls (see main Wikipedia article) in the campaign, ranked Gallagher 2nd last at 11%.

[50] On Monday, 24 October, three days before the election, Gallagher suffered a severe setback in the final debate on Pat Kenny's The Frontline, watched by an audience of 900,000.

[48][51] Later in the show, Kenny read out a tweet live on air, subsequently proven to be from an anonymous source, that the unnamed man would hold a press conference next day.

[k][51] McGuinness resumed his attack, and Gallagher, acknowledging he knew the man, called him a "convicted criminal and fuel smuggler".

[48] Gallagher then addressed the audience and, as The Irish Times would later chronicle: "he also made comments that had very unfortunate overtones for a man denying Fianna Fáil connections – including 'no recollection' and 'if he gave me an envelope'".

[48] On 25 October, UCD Professor Niamh Brennan described the BHTC accounts to The Irish Times as having a "bad vibe".

[27] On 25 October, on Pat Kenny's radio show, Gallagher questioned the motives of an audience member who asked about the €82,829[i] loan on The Frontline; however, a few minutes later, Glenna Lynch, a then-unknown housewife and mother of three with no political affiliations,[l] called into the show to reveal herself as that audience member saying: "I think it's extraordinary that Seán believes normal people, voters, don’t have the right to ask a question".

[57] On 7 March 2012, the Irish Broadcasting Authority of Ireland upheld Gallagher's complaint about unfair treatment regarding how RTÉ handled the unverified tweet on the final Pat Kenny debate.

[58] On 19 December 2017, it was reported that RTÉ agreed to pay Gallagher a sum of €130,000 as part of a confidential legal settlement arising from the final Pat Kenny debate.

[65] On the first radio debate on 10 October 2018, Gallagher said he was concerned at the "extravagance attached to the office", and that "We’ve heard stories of €3,000 a night hotels, the issue for us as taxpayers, we’re not in a position to see these figures".

[66] On 12 October 2018, Gallagher called for a public audit of all presidential expenses, which the State rejected as already covered under existing transparency guidelines.