[3] An advocate of militant protest, Moore organized demonstrations against workplace discrimination at construction sites in Philadelphia in 1963 and 1964,[4] and is best remembered for leading a picket against Girard College in 1964, which hastened the desegregation of that school.

[5] He was a champion of a wide range of causes central to the Civil Rights Movement, including integration of schools and trade unions, police brutality, and increased political and economic representation for poor African Americans.

Moore's aggressive manner and confrontational tactics alienated many leaders, black and white, including many within the NAACP who preferred negotiation "behind closed doors" over direct action.

He was a fierce critic of established civil rights leaders in Philadelphia, including lawyers A. Leon Higginbotham and Raymond Pace Alexander, and led a successful insurgency to take over the NAACP branch in 1963.

[6] Moore recruited NAACP members in working-class neighborhoods, but his harsh criticism of the black bourgeoisie and of white philanthropists led to a decline in their support for the branch under his leadership.

"[citation needed] Moore actively discouraged Martin Luther King Jr. from visiting Philadelphia [8] and he was one of the first civil rights leaders to have welcomed Malcolm X's growing role in the national movement.