Marcus "Mark" A. Bell was a visible and enterprising leader in Portland’s early Black community. His enduring commitment to "equality under the law for all" was a shared and inspirational goal for Black people and their allies in Portland and beyond. In addition to possessing considerable leadership skills, he had energy, dedication, and a collaborative nature, all of which were instrumental in forming and nurturing organizations, celebratory events, and business ventures that made a difference in Oregon.

Bell was born as a free Black in about 1825, apparently at Waltham, in Middlesex County, Massachusetts. By 1860, he had responded to the lure of the Far West and was working as a baker in the newly formed town of Healdsburg in Sonoma County, California, where he resided in the household of A. G. Dennison, a Black barber from Massachusetts. Undeterred by Oregon’s Black exclusion laws, he settled in Portland by the mid-1860s.

During the 1860s and 1870s, Bell worked as a porter and messenger for the Oregon Steam Navigation Company (OSN) and as a steward on the Oneonta, one of the company’s sidewheel steamboats. By July 1876, he was serving “Centennial Lunch[es] at the corner of Second and Washington streets, daily,” where “Mark can get up a meal you will like,” the Oregonian reported. “We’ve tried ’em and know.” Bell soon tried his hand at small business ventures, including a fish and poultry market that he and James R. Barron opened in 1877 on Morrison Street, between Third and Fourth Avenues. By the summer of 1880, he was “in charge of cuisine” at Mrs. Joseph Irvin’s Ocean House at Newport, on the central Oregon Coast.

During the 1880s, Bell drew on his experience as a messenger with the OSN and secured a salaried position at $50 a month (about $3,000 in 2023 dollars) as a paymaster’s messenger, delivering messages, payments, and orders for the Paymaster's Department at Vancouver Barracks, headquarters of the Department of the Columbia of the U.S. War Department. During the 1890s, he worked as a paymaster's messenger, also at $50 a month, for the U.S. Army Corps of Engineers in Portland.

Bell married Nellie E. Clark in September 1870. She was originally from Little York, Pennsylvania, and apparently they had no children during their short-lived marriage. On November 25, 1874, at age thirty-three, Nellie Bell died at Sutter Creek in Amador County, California, where some of her relatives lived. In December, her husband traveled to San Francisco and then to Sutter Creek to pay his respects. He never married again.

Bell’s connection to California included an association with the Elevator, a Black newspaper published in San Francisco by Philip Bell (no relation). From 1867 to 1871, Mark Bell was Portland agent for the paper and received a dollar for every five-dollar subscription he sold. He also forwarded articles and contributed pieces to the Elevator about events, conditions, and people in Portland.

Bell served twice as secretary for Portland’s Emancipation Proclamation Celebration, held in Portland on the anniversary of President Abraham Lincoln’s January 1, 1863, order "that all persons held as slaves" in the Confederate states "are, and henceforward shall be free." For the 1869 celebration, Bell organized the committees and secured the county courthouse for the program. The "colored people came pouring in[to] the city from all parts of the State,” he reported in the Elevator, “and it is estimated that there were 1300 persons present, most of whom were white.” The City of Salem, "with its patriotic and liberal hearted citizens sent 30 representatives to the celebration." The orator of the day, Rev. T. M. D. Ward, bishop of the Portland African Methodist Episcopal Zion Church, “left the impression that if this is a white man’s country, some black men are not afraid to talk in it. He was frequently interrupted by bursts of applause which shook the building."

The event ended with musical entertainments, followed by a feast and a ball in Ashler Hall above the Franklin Bookstore building owned by Samuel J. McCormick, publisher of the Portland city directory. It was "the finest celebration of any kind ever given in Portland,” Bell wrote. “It has convinced our enemies that there is talent and ability among us of a high order, and encouraged our friends to continue their labors for our full enfranchisement until we attain ‘Equality before the Law.’”

Because of Bell’s writing skills, he was often called on to serve as secretary of the organizations he helped establish. In addition to being secretary for Emancipation Festivals in 1867 and 1869, for example, he was secretary of the Ashler Club, a social club founded by Black residents of Portland in 1867, and a founding member and secretary of the first African-American Masonic Lodge in Portland, known as Hiram Lodge No. 8 (1867). He was named Oregon representative to the Co-operative Executive Committee of the National Labor Convention of the Colored Men of the United States (1869) and served as a Marshal of the Day for James Beatty, president of the Grand Ratification Jubilee (1870), Portland's celebration of the ratification of the Fifteenth Amendment. He was also secretary of the board of trustees for Portland's First A.M.E. Zion Church (1871).

Bell was active in the Republican Party and served as secretary of the executive committee for the State Colored Convention (1873). He was on the executive committee of the Portland Republican Club (1886), a member of Republican Citizens of Color (1890), and on the Committee for Blacks in Municipal Government Jobs (1891). As treasurer and executive committee member of the Lincoln [Republican] Club (1892), he was involved in the Lincoln Memorial and May Celebration (1892) and the Lincoln Memorial and Emancipation Celebration (1893).

When abolitionist and U.S. Senator Charles Sumner died in March 1874, Bell was secretary for the Portland committee that drafted resolutions honoring Sumner and called for passage of the Civil Rights bill he had written. With hopes for Sumner's Civil Rights Bill, which was later stripped of its provision for equal education, Bell was one of twenty-six founding members of the Portland Colored Men’s Protective League (May 1874), dedicated to "guarding our rights as citizens of this republic," and to using "all honest and legal means to secure the fullest recognition of our political and social rights."

When the Workingmen’s Joint Stock Association of Portland incorporated in 1869 as a real estate investment company, Bell was one of fifteen founding members—two women and thirteen men, including one white man. He served as secretary, with George Putnam Riley as president, William Brown as vice president, and Edward S. Simmons as corresponding secretary. With capital stock of $50,000 (over $1.125 million in 2023 dollars), the shareholders focused on purchasing properties in Washington Territory, mainly in the Seattle and Tacoma areas. 

Bell was also a founder of the Camp Creek Consolidated Gold and Silver Mining Company of Wasco County, incorporated at Portland in 1877 by eight men, two of them white. The company, with capital stock of $500,000 (over $14.5 million in 2023 dollars), owned thirty acres at Camp Creek, about 50 miles from Prineville in what later became Crook County (1882).  In addition to Bell, who was secretary for the company, the incorporators were William Brown, James R. Barron (vice president), Charles K. Besselleu (president), Henry Hopkins (white), Benjamin Bemer (white), William B. Robinson, and Henry Saunders. While the WJSA and Camp Creek enterprises involved significant purchases of property in Washington Territory and Oregon, no one grew rich in the process. 

In his later years, Bell still held strongly to the principle of equality under the law for all. He honored those who shared that commitment when he and George P. Riley sponsored the Reunion of Colored Pioneers in 1887. A few years later, in 1891, Bell helped organize a commemoration for the Anniversary of Haitian Independence.

Mark A. Bell died of pneumonia on October 27, 1897, at the age of seventy-two. He was buried at Lone Fir Cemetery. No marker identifies his grave.