Harte's achievements as an arts activist are many and significant. In 1985 he set up the Writers' Project at Lucan Vocational School to confront the total absence of professional structures for writers, and pioneered the use of the then new Social Employment Scheme for the purposes of developing the arts. He employed the first official Writer-in-Residence in Ireland during 1985/86 in Lucan - establishing the pattern for this scheme afterwards widely used as a support mechanism for writers. He also set about the twin aims of establishing a Writers' Union and a national Writers' Centre. He established the Irish Writers' Union in January, 1987, and it quickly became a recognised and dynamic force in effecting improvements in conditions for writers. In the same year he got a commitment from the government to make a state building available for a Writers’ Centre, and secured a grant of £100,000 from the National Lottery to establish it. With the involvement of the writers' organisations and the support of a wide range of writers, he negotiated a joint project with Matt McNulty of Dublin Tourism who was in the process of setting up the Dublin Writers' Museum at Parnell Square, and in 1991 the Irish Writers' Centre finally opened at 19 Parnell Square. Harte retired from active involvement, but not before he had also initiated the move to set up a copyright agency in Ireland. Here in an Irish Times article, Harte describes, on its twenty-fifth anniversary, how he founded the Irish Writers' Centre.

In 2009 the Irish Writers’ Centre was on the point of closing because state funding had been withdrawn completely. Harte returned to the Board of Directors and became Chairman once more, working with other activists and supporters to rescue the stricken Centre. An enormous voluntary effort, coupled with the overwhelming support of the literature community and the general public, has ensured that the Irish Writers' Centre is still open and vibrant, still developing and promoting writers and writing. And having served his four years at the helm, Harte again retired from active involvement in 2012. His final project was to organise Read for the World, a marathon reading that set a new Guinness World Record for the Irish Writers' Centre. The Irish Times has lauded the effort to save the Centre: see here and here. The Guardian has also praised the work done at the Centre: see here, as has the Corriere della Sera: see here.