He began serving as Senate chaplain on June 27, 2003, becoming the first African American and first Seventh-day Adventist to hold the office.

[2] Commissioned as a Navy chaplain in 1976, Black's first duty station was the Fleet Religious Support Activity in Norfolk, Virginia.

[3] During the 16-day United States federal government shutdown of 2013, Black's invocations began to garner widespread national attention.

On October 1, the first day of the shutdown, he prayed for divine guidance to "strengthen our weakness, replacing cynicism with faith and cowardice with courage".

"[6] On day nine, prompted by news of the delay of death benefits for military families, Black prayed, "It's time for our lawmakers to say 'Enough is enough'", and asked that God "cover our shame with the robe of Your righteousness".

[6] In 1995, Black was chosen from 127 nominees for the NAACP Renowned Service Award for his contributions to equal opportunity and civil rights.

In 2004, the Old Dominion University chapter of the NAACP conferred on him the Image Award, "Reaffirming the Dream - Realizing the Vision", for military excellence.

[2] On May 23, 2019, Black was awarded the Becket's 2019 Canterbury Medal[7] for his defense of religious liberty for people of all faiths.

[10]As a result of the attention his invocations received during the federal government shutdown, Black was parodied on NBC's Saturday Night Live.

Playing Black during the show's "Weekend Update" segment that aired on October 12, 2013, SNL cast member Kenan Thompson prayed, "Lord, bless and forgive these braying jackasses."