To some extent, one could say that Eisenhower's Modern Republicanism was a slight modification of Truman's Fair Deal. Some of the more extreme members of the GOP wanted to see Truman's policies dismantled altogether. They thought that government had become too big and was involving itself too much in the lives of individuals and businesses alike.
But Eisenhower was more pragmatic. He'd criticized Truman during the 1952 presidential election campaign for giving too much power to the state. Yet, at the same time, he still believed that some measure of government control was necessary for the maintenance of a stable economy and a just society. Eisenhower saw his approach as a middle way between the unfettered concentration of wealth and the unbridled power of the state. Truman's Fair Deal, on this reading, had gone too far towards the latter.
In its stead, Eisenhower favored what he thought was a more moderate alternative to the big government approach of the Fair Deal. Individual freedom and the market economy would be preserved, but the government would still have a role to play in protecting those who could not help themselves. To that end, Eisenhower even extended the role of government in some areas. He expanded Social Security, increased the minimum wage, and created the Department of Health, Education, and Welfare. He also supported the construction of low-cost public housing, though was prepared to spend much less than Truman.
Eisenhower also presided over an extensive improvement of the nation's infrastructure, something that would not have been out of place under Truman's Fair Deal. Yet as a Republican, Eisenhower was more instinctively averse to public spending than his predecessor. During his second term he used his veto to block a number of expensive programs supported by the Democratic Congress. Despite Eisenhower's best efforts, however, domestic spending continued to rise considerably.