The Irish people set out for America to escape British mercantilism, economic recession, increasing violence of terrorists groups, and the Great Famine. Most Irish people entering the United States between 1818-1870 came as refugees from disaster; they were running away from misery and death rather than rushing towards freedom and opportunity.

Nevertheless, they had put great hope for their new life. But their dreams were disillusioned as soon as they set foot on the ship which was supposed to bring them to America. Living Conditions on these ships, often referred to as "Coffin Ships," were so horrible that for the first time doubts arose whether their new life would be better than the old.

If they survived the long journey and arrived in America, these immigrants learned that life was going to be a battle for survival. Hundreds of runners, usually large greedy men, swarmed aboard the ship grabbing immigrants and their bags trying to force them to their favorite tenement house and then exact an outrageous fee for their services. The tenements they were put in were in a horrible condition; Cellar tenement's were unsuitable for any living creature but the Irish lived in these tenements where floors ranged from ten to thirty feet below high-water mark! 'In sub-tidal basements often more than a dozen families lived cramped together beneath the level of the sea. In very many cases the vaults of privies were situated on the same or a higher level, and their contents frequently oozed through walls into the occupied apartments beside them. These living conditions bred sickness and early death. It was estimated that 80% of all infants born to Irish immigrants in New York City died

In order to improve the living conditions of the Irish Immigrants, who weren’t very well educated for they had led a rural lifestyle, they were forced to acquire unskilled labor and work their way up. But this climb to success was long and hard.

During the period of peak immigration the Irish people were forced into jobs that demanded many hours of hard physical labor with very little pay. Irish immigrants often entered the workforce at the bottom of the occupational ladder and took on the menial and dangerous jobs that were often avoided by other workers. Many Irish women became servants or domestic workers.

Americans disdained this type of work, fit only for servants, the common sentiment was: "Let Negroes be servants, and if not Negroes, let Irishmen fill their place..."

Many Irish men labored in coal mines and built railroads and canals. Railroad construction was so dangerous that it was said that there was an Irishman buried under every tie. Usually, other jobs were not available for the Irish

Advertisements for employment often were followed by "NO IRISH NEED APPLY".

http://tigger.uic.edu/~rjensen/no-irish.htm

Catholics were used to living in rural communities; they lacked the knowledge and skills needed to succeed in urban, Protestant Anglo-Saxon society. The Irish people realized they were uneducated, unskilled, and lacked the skills required to survive in the city.

The American people feared the mass Catholic migration of unskilled and uneducated Irish workers because they were scared of the effects the Irish would have on the economy and their way of life. The American's fear was often associated with a loathing that sprung from the poor living conditions and the  low social class of the Irish. The Irish people realized they had to first overcome their lack of education and skill before they could fight for a higher social class. This fight for jobs and education led to years of strife, but the Irish knew they had to take it one day at a time to succeed in a society in which they rewarded the hardworking and courageous.

Not knowing how to "behave" in the beginning, they provoked scorn; they were compared with African Americans and almost treated in a similar way. A common saying in the USA was:

"The Negro is black outside; the Irishman is black inside", showing very drastically how little they were welcome.

The resentment against the Irish wasn’t only uttered in private, it was also published in newspapers:

The Chicago Post for example wrote, "The Irish fill our prisons, our poor houses...Scratch a convict or a pauper, and the chances are that you tickle the skin of an Irish Catholic. Putting them on a boat and sending them home would end crime in this country."

Instead of trying to improve their image by becoming friends with the Americans, they united and took the offence. Especially at the beginning, insult or intimidation was often met with violence.

The Church played an integral part in their lives. It was a militant church which fought not only for their souls but also for their human rights.

After the religious riots in Philadelphia, during which many Catholic churches were burned, the mayor of New York asked Archbishop Hughes, "Do you fear that some of your churches will be burned."

"No sir, but I am afraid some of yours will be. We can protect our own."

Later, public officials asked the Archbishop to restrain New York's Irish. "I have not the power," he said. "You must take care that they are not provoked." No Catholic church burned in New York.

Since they knew that their dream of leading a successful life for which they had sacrificed so much could only come true if they got educated and adapted to the American way of life, the Irish often became more "Americanized" than the Americans.

So, little by little the days of "No Irish Need Apply" passed; St.Patrick's Day parades replaced violent confrontations. The Irish not only won acceptance, but persuaded everyone else to become Irish at least for St.Patrick's Day.

In 1850 at the crest of Potato Famine immigration, Orestes Brownson, a celebrated convert to Catholicism, stated: "Out of these narrow lanes, dirty streets, damp cellars, and suffocating garrets, will come forth some of the noblest sons of our country, whom she will delight to own and honor."

In little more than a century his prophecy came true. Irish-Americans had moved from the position of the despised to the Oval Office.

The Irish faced many problems throughout the nineteenth century but these hardships and struggles gave them the strength they needed to succeed in America. America offered one thing that Ireland could not offer these people, hope for the opportunity to succeed in life. The military first contributed to many problems of the Irish, such as the deterioration of the family structure, but it also aided them in breaking the remaining ties to Irish nationalism, and gave the people a chance to receive an education.

During the Civil War, when America recruited the recent wave of Famine Irish immigrants to fight for their country, 144,000 of them volunteered to fight for the Union. Others, in smaller numbers, fought for the Confederate States. Since the military was basically their only chance to achieve success in the U.S.A., the Irish fought passionately for the Americans.

World War I brought the Irish respect by American society; their fierce conduct in many military operations allowed them to break from Ireland's nationalism and depend on themselves and their new home for success. World War II furthered this success by providing the Irish soldiers with an opportunity to seek education at the expense of the country they defended. The G. I. Bill sent many Irish-Americans through college, giving them the education they needed to make a significant jump from a simple peasant to such positions as lawyers, doctors, and professors. This movement along with the new skills accumulated in the factory allowed the Irish-Americans to move out of the ghettos and into respectable housing; leaving disease and poverty behind them.