Mortensen plays Tony Lip, an earthy Italian-American guy who in real life (his full name was Frank Anthony Vallelonga) worked as a bouncer at the old Copacabana nightclub in Manhattan and went on to become an actor most known for his crime boss role in “The Sopranos” television series. As shown in “Green Book,” he is tough as nails, can handle anyone obstreperous, has contacts with mobsters and comports himself with crude dignity. He is also a devoted husband and father.

When the Copa closes for renovations, leaving him in need of a job, he is recommended on the basis of his reputation to be a driver for popular African-American musician, pianist Don Shirley, whose trio is booked on a tour that includes stops in the deep south. Shirley, played haughtily by Ali, lives in fancy digs above Carnegie Hall. He sits on a throne-like chair and as we see as the film develops, distances himself from his African-American heritage in an effort to carve out his own aloof life. As a musician, Shirley is deeply frustrated by not being able to gain recognition as a classical pianist.

In the initial face-off, we see how different the men are from each other. Tony is brash and rebels against the job, which is supposed to include butler as well as driving duties. He walks out. Shirley is intrigued as well as aghast at Tony, and calls on him to take the job just as driver (no butler duties), which will mean that Tony must be away from his family for two months.

What follows is the story of how each man educates the other, bonds develop even amid the inevitable arguments, and Tony proves to be just what Shirley needs to get the protection required when the gigs are in the South, where although Shirley is the attraction who draws the elite, he isn’t supposed to eat or use toilet facilities in the places where the trio performs. The film’s title refers to the guide book detailing hotels and restaurants where blacks can stay and eat while traveling in the segregated south. Tony is appalled at such inequality. In the course of all that occurs, Shirley is increasingly led to become more down to earth and honor his ethnicity.

There are many amusing moments in the saga, as when Shirley helps Tony polish letters to his wife, Dolores, warmly portrayed by Linda Cardellini, and when Tony gets Shirley to eat fried chicken. The behavioral clashes counterpoint the grim moments when Shirley has to be rescued from racists.

There is one particular unlikely situation in the screenplay by Nick Vallelonga (Tony’s son), Brian Currie and Farrelly, at least in the way the scene is depicted. On a rainy night in the south the car with Tony and Shirley is stopped by two cops and both are ordered to step out of the vehicle. Instead of politely responding to the officers by telling them that Shirley, the black man in the back seat, is a famous musician due for a concert, Tony not only fails to do that logical thing, but loses his temper and hits one of the cops while the other has his gun drawn. Can one doubt that so blatantly assaulting a cop in that racist milieu would have resulted in the men being shot on the spot? Even in the north today that could happen. However, as handled in the film, the two are merely arrested until they are freed as a result of a phone call by a very important person. I am not in a position to question what happened in the real-life story, only the way the scene is presented to us on screen.