Martin Luther King, Jr. was a leader of the Civil Rights movement who faced enormous challenges in his lifetime. His first major protest was the Montgomery, Alabama, bus boycott of 1955-1956, when he, along with Rosa Parks, protested conditions that African-Americans faced on buses in that city. Under the laws of Jim Crow, African-Americans were forced to move to the back of the bus in Montgomery and other southern cities when whites boarded, and African-American riders were often treated unfairly and rudely. From the outset, Dr. King faced hostility from segregationists, and his life was threatened repeatedly. For example, during the bus boycott, his house was bombed, and he was arrested during a campaign to desegregate the city of Birmingham, Alabama (he was jailed several times during his lifetime).
Dr. King also faced life-long depression and the tension of uniting African-Americans and sympathetic whites into a movement that would achieve his goals. He advocated a policy of non-violence, inspired by ideas of Gandhi and others, and started the Southern Christian Leadership Conference (SCLC). In the 1960s, several civil rights groups developed, such as SNCC (Student Non-Violent Coordinating Committee). Leaders of SNCC thought that Dr. King was not connected with their concerns as younger members of the Civil Rights movement. Later leaders, such as Malcolm X, a Muslim, often believed in more direct and violent confrontations to achieve their aims than Dr. King did (though Malcolm X became more convinced of the power of non-violence before he died).
Another of Dr. King's challenges was to convince the federal government to become involved in helping the Civil Rights movement. At times, this pressure could take a long time to result in legal changes. For example, during the Montgomery Bus Boycott, the Supreme Court eventually passed a law (in December of 1956) that supported a lower court's ruling outlawing segregation in busing in Montgomery, Alabama. However, the boycott had already been going on for more than a year at this point, forcing African-Americans to walk or carpool to get to work or school. In addition, federal laws to protect the civil rights of African-Americans on a national scale took a long time to pass; finally, in 1964, the national Civil Rights Act was passed. The Voting Rights Act, passed in 1965, was passed to protect the rights of all citizens, including African-Americans to vote. This act was the result of a long period of pressure that the SCLC and SNCC and others had put on the federal government to protect voting rights. In addition, the movement had to endure a great deal of violence and hatred before this law was passed.
Dr. King also turned to issues that were difficult to solve. For example, in 1968, he went on the Poor People's Campaign to improve jobs and housing for African-Americans, particularly in urban areas. These issues were difficult to solve, and when Dr. King was assassinated in April of 1968, he was still trying to solve these types of difficult issues of economic inequality that are still present in the U.S. Therefore, Martin Luther King, Jr. faced enormous challenges, including violence, the problems of uniting his movement, the problem of pressuring the federal government for change, and the problem of inequality, among others.