According to Keynesianism, choices took by the private sector occasionally have ineffective macroeconomic outcome. As a consequence, this school of macroeconomic idea supports the usage of vigorous strategy and fiscal response measures by making use of the public sector, monetary policy actions started by the central bank and fiscal policies espoused by the government with the leading objective of steadying business cycle output. Keynesianism encourages for the practice of a mixed economy, which includes largely the private sector and the government with the public sector performing a significant role. This was the economic version implemented during the last part of the Great Depression, the World War II, and the post-war economic expansion observed during 1945-1973. Keynesianism lost its stimulus during the 1970s economic decline and counter-revolution. The recent global financial crisis has caused the rebirth of Keynesian theory in economic models. This essay will describe Keynesianism and will then try to explain its rise and fall. Keynesian economics also called Keynesianism is an economic ideology of total spending in the economy called aggregate demand and its influence on output and inflation. Keynesian economics was created by the well-known British economist John Maynard Keynes in 1930 in an effort to apprehend the Great Depression. Keynesianism led economics theories and policy after world war II until late 1970s (Kenton, 2019). Keynes was in favor for expanded government expenditures and put down taxes to increase demand and take the global economy out of the slump. Consequently, Keynesian economics was utilized to refer to the notion that ideal economic execution could be reached, and economic crashes avoided by shaping aggregate demand via activist equilibrium and economic interference policies by the government. Keynesian economics is viewed as a “demand-side” idea that concentrates on changes in the economy over the short term. (jahan, mahmud and papageorgiou, 2014)>