In the recent past, Saint Patrick's Day was celebrated only as a religious holiday. It became a public holiday in 1903, by the Bank Holiday (Ireland) Act 1903, an Act of the United Kingdom Parliament introduced by the Irish MP James O'Mara. O'Mara later introduced the law which required that pubs be closed on March 17, a provision which was repealed only in the 1970s. The first St. Patrick's Day parade held in the Irish Free State was held in Dublin in 1931 and was reviewed by the then Minister of Defence Desmond Fitzgerald. Although secular celebrations now exist, the holiday is still a religious observance in some areas.

It was only in the mid-1990s that the Irish government began a campaign to use Saint Patrick's Day to showcase Ireland and its culture. The government set up a group called St. Patrick's Festival, with the aim to:

   —Offer a national festival that ranks amongst all of the greatest celebrations in the world and promote excitement throughout Ireland via innovation, creativity, grassroots involvement, and marketing activity.
   —Provide the opportunity and motivation for people of Irish descent, (and those who sometimes wish they were Irish) to attend and join in the imaginative and expressive celebrations.
   —Project, internationally, an accurate image of Ireland as a creative, professional and sophisticated country with wide appeal, as we approach the new millennium.

The first Saint Patrick's Festival was held on March 17, 1996. In 1997, it became a three-day event, and by 2000 was a four-day event. By 2006, the festival was five days long.

Many Irish people still wear a bunch of shamrocks on their lapels or caps on this day or green, white, and orange badges (after the colours of the Irish flag). Girls and boys wear green in their hair. Artists draw shamrock designs on people's cheeks as a cultural sign, including American tourists.

Although Saint Patrick's Day has the colour green as its theme, one little known fact is that blue was once the colour associated with this day.

The biggest celebrations on the island of Ireland outside Dublin are in Downpatrick, Northern Ireland, where Saint Patrick was buried following his death on March 17, 493. In 2004, according to Down District Council, the week-long St. Patrick's Festival had over 2000 participants and 82 floats, bands, and performers, and was watched by over 30,000 people.

The day is celebrated by the Church of Ireland as a Christian festival. Saint Patrick's Day as a celebration of Irish culture was rarely acknowledged by Northern Irish loyalists, who consider it a festival of the Irish Republicans. The Belfast City Council recently agreed to give public funds to its parade for the first time; previously the parade was funded privately.[citation needed] The Belfast parade is based on equality and only the flag of St. Patrick is supposed to be used as a symbol of the day to prevent it being seen as a time which is exclusively for Republicans and Nationalists. This allowed both Unionists and Nationalists to celebrate the day together. The Unionists (orangemen) wear orange instead of green on St. Patrick's day; both colors are in the Irish flag, and orange represents the protestants of Northern Ireland.