Mr. Destiny

The story begins on "the strangest day" of Larry Burrows' (James Belushi) life (his 35th birthday) consisting of a series of comic and dramatic misadventures. Larry, who blames all of his life's problems on the fact that he struck out during a key moment of his state high school baseball championship game on his 15th birthday, wishes he had done things differently. His wish is granted by a guardian angel-like figure named Mike (Michael Caine), and appears at various times as a bartender, a cab driver, and so on. Larry soon discovers that Mike has transferred Larry into an alternative reality in which he had won the pivotal high school game. He now finds himself rich and (within his company) powerful, and married to the boss' (Bill McCutcheon) sexy daughter Cindy Jo Bumpers (Rene Russo). At first, his new life seems perfect, but he soon begins to miss his best friend Clip Metzler (Jon Lovitz) and wife Ellen (Linda Hamilton) from his previous life; he also discovers that his alternate self has created many enemies, like Jewel Jagger (Courteney Cox), and as Larry's problems multiply, he finds himself wishing to be put back into his old life.
The story begins with Larry's car, an old Ford LTD station wagon, stalled out in a dark alley. Suddenly the pink lights of "The Universal Joint," a bar, come on. Larry goes inside to call a tow truck, and tells bartender Mike his troubles. He reviews the day he just had, which ended with his getting fired after discovering his department head Niles Pender's (Hart Bochner) scheme to sell the company under the nose of its owners to a group of naive Japanese investors. He tells Mike that he wishes he'd hit that last pitch out of the park, after which Mike fixes him a drink called "The Spilt Milk." The Spilt Milk was a drink that gave him his wish that he hit that home run in that championship game.
Larry leaves the bar, walks home (his car apparently towed) and discovers someone else living in his house, which is now fixed up (previously his yard and driveway were muddy and unfinished). Mike appears as a cab driver and drives him to his "new" home, a mansion in Forest Hills, explaining that he did in fact hit the last pitch and won the game. He soon discovers that Cindy Jo is his wife and he's the president of his company, Liberty Republic Sporting Goods. Being a classic car buff, he's shocked to find that he owns a collection of priceless antique automobiles.
Larry soon discovers that Clip has a low-level job in the accounting department and is quite insecure, as opposed to the jokester he was before. Ellen is shop steward (in both realities) and is married to another man. Jewel, a forklift operator in the previous reality, is now Larry's mistress and his secretary. Ellen hates Larry and he discovers that the union is threatening a walkout due to massive layoffs and increased production, since Niles is selling Liberty Republic in both realities. Seeing Ellen, he realizes how much he misses her and agrees to all the union's demands, providing Ellen agrees to dinner at his favorite restaurant. She reluctantly agrees, and Larry eventually convinces her that they were married in a previous life.
After discovering that Larry has agreed to union demands, Niles takes revenge, by telling both Cindy Jo and Jewel of Larry's dinner date with Ellen. He then plots to kill Larry at the office that night. However, company owner Leo Hansen arrives to deliver a note to Larry, announcing his termination, and Niles kills him by mistake. Discovering the note, Niles calls the police who attempt to arrest Larry for Leo's murder. Larry escapes while jealous Jewel creates pandemonium outside in her attempts to shoot him (and shoots out a number of police cars in the process), leading to a police chase. Larry is eventually cornered in a dark alley but the pink glow of "The Universal Joint" comes on and he runs into the bar. Unable to find Mike, Larry attempts to make the "Spilt Milk" himself, the ingredients clearly aged.
The flashing lights of the police cars appear and Larry surrenders but instead of cops, a tow truck driver named Duncan enters (the police car lights now tow truck lights). Confused at first, Larry sees Mike back behind the bar and realizes he's back in his old life. Larry thanks Mike for everything and, upon exiting the bar, suddenly realizes that the deal with the Japanese investors is happening shortly. Driven by Duncan to company headquarters, Larry barges into the boardroom, decks Niles and exposes his scheme just as Leo is about to sign the deal.
Thinking everyone forgot his birthday, Larry returns home (which still has the muddy driveway and lawn) to a surprise party with his family and friends in attendance. Soon after, Cindy Jo and her husband Jackie Earle (Jay O. Sanders), the company president arrive. Jackie offers Niles' job to Larry, plus a company car, a new Mercedes and he accepts.
Back in the past, young Larry is about to leave the stadium, still upset about the loss, when he's approached by a mysterious stranger (Mike) who reassures him that everything will be alright. Larry thanks him for the reassurance, but walks off wondering who Mike thinks he's kidding.

Question: Who is the bartender?
Answer: Mike