Grant was born in St. Louis and educated at Sumner High School, the University of Michigan, and Howard Law School in Washington, D.C. He was admitted to the Missouri Bar in 1930. He devoted his life to the civil rights cause and was nationally recognized for his work in the civil rights movement. He is credited with playing an important role in changing the political orientation of black St. Louis from Republican to Democratic in the 1930s. He became director of legislative research for the St. Louis board of aldermen, a post which he held for almost 30 years.