In 1964, at Johnson's request, Congress passed the Revenue Act of 1964 and the Economic Opportunity Act, as part of the war on poverty. Johnson set in motion legislation creating programs such as Head Start, food stamps and Work Study. During Johnson's years in office, national poverty declined significantly, with the percentage of Americans living below the poverty line dropping from 23 percent to 12 percent.  Johnson took an additional step in the War on Poverty with an urban renewal effort, presenting to Congress in January 1966 the "Demonstration Cities Program". To be eligible a city would need to demonstrate its readiness to "arrest blight and decay and make substantial impact on the development of its entire city." Johnson requested an investment of $400 million per year totaling $2.4 billion. In the fall of 1966 the Congress passed a substantially reduced program costing $900 million, which Johnson later called the Model Cities Program. Changing the name had little effect on the success of the bill; the New York Times wrote 22 years later that the program was for the most part a failure.  Johnson's initial effort to improve healthcare was the creation of The Commission on Heart Disease, Cancer and Strokes (HDCS). Combined, these diseases accounted for 71 percent of the nation's deaths in 1962. To enact recommendations of the commission, Johnson asked Congress for funds to set up the Regional Medical Program (RMP), to create a network of hospitals with federally funded research and practice; Congress passed a significantly watered down version.  As a back-up position, in 1965 Johnson turned his focus to hospital insurance for the aged under Social Security. The key player in initiating this program, named Medicare, was Wilbur Mills, Chairman of the House Ways and Means Committee. In order to reduce Republican opposition, Mills suggested that Medicare be fashioned as a three layer cake--hospital insurance under Social Security, a voluntary insurance program for doctor visits and an expanded medical welfare program for the poor, known as Medicaid. The bill passed the house by a margin of 110 votes on April 8. The effort in the Senate was considerably more complicated; however, the Medicare bill passed Congress on July 28 after negotiation in a conference committee. Medicare now covers tens of millions of Americans. Johnson gave the first two Medicare cards to former President Harry S Truman and his wife Bess after signing the Medicare bill at the Truman Library in Independence, Missouri.

Answer this question "Why did he feel he needed to act?" by extracting the answer from the text above.
During Johnson's years in office, national poverty declined significantly, with the percentage of Americans living below the poverty line dropping from 23 percent to 12 percent.