Speaking on the 60th anniversary of a landmark Supreme Court ruling outlawing segregation in public schools, Holder said that public outrage over recent instances of bigoted remarks by well-known people did not mean the struggle for civil rights is over.
"These outbursts of bigotry, while deplorable, are not the true markers of the struggle that still must be waged, or the work that still needs to be done - because the greatest threats do not announce themselves in screaming headlines. They are more subtle. They cut deeper," he said in a prepared commencement address at Morgan State University in Baltimore.
"... We ought not find contentment in the fact that these high-profile expressions of outright bigotry seem atypical and were met with such swift condemnation."
Holder, the nation's first African-American attorney general, didn't mention a specific case but racist comments by the owner of the NBA's Los Angeles Clippers, Donald Sterling, that were made public last month received substantial media attention and were widely condemned by the league, players, public officials and on social media.
Since the 1954 Brown vs. Board of Education Supreme Court decision, Holder said laws that are overtly discriminatory no longer survive the "strict scrutiny" legal standard.
He said the new battleground against discrimination should focus on policies and laws that appear race-neutral but in practice impede equal opportunity.
"This is the work that truly matters - because policies that disenfranchise specific groups are more pernicious than hateful rants," Holder told the graduates at Morgan State, a historically black college.
He cited disciplinary practices in schools that punish black males at three times the rate of their white peers. He also said a report last year by the U.S. Sentencing Commission found that black men receive criminal sentences that are nearly 20 percent longer than white males convicted of similar crimes.
Holder said restrictions on voting that are justified as attempts to curb voter fraud disproportionately disenfranchise blacks, Hispanics and other minorities.