Joe Morton (“Scandal”) is giving one of the most riveting performances in town as comedian/activist Dick Gregory in this biographical play by Gretchen Law now at the Westside Theatre. Most of the action is set in the 1960’s when Gregory was building his career. Hugh Hefner gave him an important break with a gig at the Playboy Club, where his first performance was before an audience of hostile white Southerners. Gregory turns down appearing on the "Tonight" show until Jack Paar personally offers him the opportunity to be the first black performer invited to sit on the couch. We see Gregory onstage delivering uproarious highlights from his act as well as offstage at critical moments in his life. His close relationship with Medgar Evers is explored as an important influence. There are scenes set in the near present that are less compelling, but reveal Morton’s subtlety in portraying Gregory as an octogenarian. The only other person onstage from time to time is the fine John Carlin in a variety of small roles including emcee, heckler, stage manager and cab driver. Chris Barreca’s set design is basic. John Gould Rubin’s direction is smooth. Morton’s performance is simply too good to miss. Despite being selected by the Times as a Critic’s Pick, there were empty seats. The diverse audience made up in enthusiasm what it lacked in numbers. Running time: 90 minutes, no intermission.