When I first saw Rosa Parks at an NAACP dinner almost two decades ago, she was a frail woman in her 70s. Her speech that night was delivered in a voice so soft that her words were at times undecipherable. But her story was already familiar to listeners, who came more to see her (and to say they had seen her) than hear a speech. By that time, Parks' public identity had been shaped by the moment in December 1955 when she refused to give up her bus seat to a white man. By then her ritualized public retelling of her act of defiance had become her livelihood.

My joy at being introduced to her was balanced by the sadness of seeing her greatness confined by old age. She had become famous as the woman whose arrest ignited the Montgomery bus boycott movement, but I knew that there was so much more to her story. I was less interested in the bravery she spontaneously displayed on the bus than in the courage she manifested throughout her life.

I admired her most as a long-distance runner of the modern African American freedom struggle. Parks's infirmities obscured her essential stamina — that is, her longstanding commitment to the cause of racial justice.

During the 1930s, she and her husband Raymond risked violent retaliation from white racists when they became involved in the controversial Scottsboro defense campaign, which saved nine black teenagers from death sentences on trumped-up rape charges. After enduring threats and accusations of Communist ties, Raymond Parks withdrew from political activism, but his wife became a stalwart of Montgomery's NAACP branch.

During World War II, Parks enthusiastically supported the Double-V campaign launched by African-Americans determined to defeat racism at home as well as fascism abroad. When her younger brother was inducted into military service while still unable to vote, she decided to join the Montgomery Voters' League. After several attempts, she managed to register and voted for the first time in 1946.

She began to work closely with E. D. Nixon, the NAACP activist who was also a labor organizer affiliated with A. Philip Randolph's Brotherhood of Sleeping Car Porters. Nixon often referred to Parks as "his secretary," but her elected role in the NAACP branch was vital to its emergence as an important force in Montgomery race relations during the early 1950s.

Parks rarely spoke in public, but she was well known among the Montgomery civil rights proponents who prepared the way for the boycott. Following the Supreme Court's Brown v. Board of Education decision in 1954, she began advising the branch's youth group. When one of these young activists, 15-year-old Claudette Colvin, was arrested in March 1955 for refusing to give up her seat to a white man, Parks consulted with black attorney Fred Gray to arrange for Colvin's legal defense.

Neither Colvin's case nor the subsequent arrest of 18-year-old Mary Louise Smith prompted a mass protest by Montgomery's black residents, but Parks' disappointment that their cases attracted little notice doubtless spurred her own willingness to become a legal test case after her arrest. Unlike the teenagers, Parks was a middle-aged, churchgoing resident who was widely respected in the black community for her contributions to civil rights reform.

Parks's activism brought her into contact with Martin Luther King, Jr., the youthful pastor of Montgomery's Dexter Avenue Baptist Church. Soon after King's arrival during 1954, Parks and Ralph Abernathy— pastor of the city's First Baptist Church — encouraged the newcomer to become involved in the NAACP branch.

In January 1955, when King agreed to deliver an address to mark the installation of NAACP officers, Parks' notes provide the only surviving record of King's first civil rights address in Montgomery. According to her notes, King applauded the Brown decision as an important advance, but added, "We have come a long way, but still have a long way to go." Parks would later write to King to invite him to serve as on the branch's executive committee, explaining that King's "outstanding contribution" to the NAACP merited the appointment.

Through her friendship with Montgomery's foremost white liberals — Virginia and Clifford Durr — Parks was able to attend Tennessee's Highlander Folk School during the summer of 1955. A center for labor organizers, Highlander would become a training ground for civil rights workers of the 1950s and 1960s. While there, Parks took part in a workshop titled "Racial Desegregation: Implementing the Supreme Court Decision."

Parks returned from Highlander with a spirit of resistance that had been strengthened by years of quiet militancy. Her arrest a few months later sparked a mass movement that attracted large numbers of women as well as men, working-class people as well as professionals of all ages and educational backgrounds.

Parks and her husband endured threats and reprisals after the boycott began. Unlike King, they did not have jobs that were secure from racist retaliation. For Rosa Parks, fame brought harassment and a forced move to Detroit. Fame's financial rewards would only come gradually. The large speaking fees she would receive during the final decades of her life came not from her courageous act in 1955 but from the human rights revolution that she set in motion.

Parks worked until retirement in the office of U.S. Rep. John Conyers, D-Mich. Only then did she become the frail celebrity I met during the 1980s. In 1987, she founded the Rosa and Raymond Parks Institute for Self-Development in Detroit. During her final years, she received countless awards, including the Presidential Medal of Freedom and the Congressional Gold Medal.

Rosa Parks received the accolades she long deserved. As we remember her life, perhaps we can also find ways to acknowledge other long-distance runners who quietly devote their lives to making the world better.

Clayborne Carson is a history professor and director of the Martin Luther King Jr. Research and Education Institute at Stanford University. He wrote this commentary for The Advertiser.