Mark starts out as a radical at Walden College, and leads several peace rallies (in his first appearance, he referred to himself as "'Megaphone' Mark Slackmeyer"). The character was initially modeled after a Yale undergraduate activist, Mark Zanger. Mark seized the office of Walden's President King twice (he considers the first time a failure as President King was far too cooperative), and in 1972 took a cross-country trip with Michael Doonesbury to Washington, and eventually to that year's Republican National Convention in Miami, Florida.