Spacey, a US citizen currently residing in the UK while serving as artistic director of London theatre The Old Vic, succeeds James Gandolfini, who is famous for playing mobster Tony Soprano, in American's UK ads.
In the McCann Erickson-created 40-second TV ad Spacey is shown trying a variety of different seats at a theatre, a library and a New York basketball game.
He finally finds contentment in the American Airlines business seat.
The ad is an evolution of the previous campaign featuring Gandolfini, which played on the idea that New Yorkers like him make the most demanding travellers.
According to McCann Erickson creative directors Brian Fraser and Simon Learman, American is now focusing on the "discerning traveller".
They said: "There is no one who better exemplifies this testy, urbane traveller than the director of The Old Vic, and two-time Oscar winner, Kevin Spacey."
The ad was directed by Michel Gondry, who directed 'Eternal Sunshine of the Spotless Mind', and produced by Partizan with post-production by The Mill. The art director was Clive Yaxley.
The campaign also includes 20-second TV spots covering the benefits of the lie-flat bed in the business class cabin and the efficiency of the flagship check-in and JFK airport lounge.
Media planning and buying is handled by Universal McCann.