Justice Smith was born in Lakeland, Florida in 1927. His father was Cuban. His mother was African American. He graduated from Temple University in 1952 and from the University of Washington School of Law in 1955. He served as a law clerk for Washington Supreme Court Justice Matthew W. Hill (1955); as a deputy prosecuting attorney for King County (1956-60); and as a special assistant to United States Attorney General Robert F. Kennedy (1960-64).

His career includes service as a judge of the Seattle Municipal Court (1965-66) and as a judge of the King County Superior Court (1966-73). He was associate dean and professor of law at the University of Washington and retired in 1983 as professor emeritus. He was a news commentator for KOMO Radio and Television (1973-79) and retired from the United States Marine Corps Reserve with the rank of Lieutenant Colonel (1986). He had prior service in the United States Army (1945-46).

Justice Smith has served in local, national, and international organizations concerned with religion, law, health, children and families, human rights, and cultural diversity. He was appointed by President William J. Clinton on June 5, 1999 to the United States Commission on International Religious Freedom created by Congress in 1998 under the International Religious Freedom Act. He co-chairs with Justice Charles W. Johnson the Supreme Court Minority and Justice Commission. He served as moderator of the National Consortium of Task Forces and Commissions on Racial and Ethnic Bias in the Courts until May 1, 1999. He chaired the American Bar Association Task Force on Minorities in the Judiciary, Judicial Division, until 1997. His service awards include: 1988 Lawyer of the Year Award, Seattle-King County Bar Association; Public Service Award, United States Department of Justice Community Relations Service (1988); 1989 Volunteer of the Year Award, American Cancer Society; 1989 Alpha Phi Alpha Distinguished Service Award; 1990 Edwin T. Pratt Award, Seattle Urban League; 1990 Distinguished Alumnus Award, University of Washington School of Law; 1994 Kappa Alpha Psi Distinguished Judicial Service Award; 1995 African American Legislative Committee Distinguished Service Award; 1996 Silver Gavel Award, Washington State Hispanic Bar Association; 1996 Hispanic Judge of the Year Award, Hispanic National Bar Association; 1997 Outstanding Judge Award, King County (Washington) Bar Association; and 1999 Don Kazama Human Relations Award, Japanese American Citizens League, Seattle Chapter.