It's a series of famous TV commercials for Miller Lite beer, known as the Miller's "Lite Beer All-Stars" ad campaign by McCann-Erickson.
Steve starred in about 4 separate commercials from the campaign, but was involved in about 10 in total with smaller roles in the others. Full list is near the bottom of this page.
Steve Mizerak Miller Lite "Just Showing Off"
This is the Steve Mizerak Miller Lite commercial from 1978-11-20, and this is the one that really made him famous. Steve's lines from the commercial are as follows:
When you shoot a lot of pool in bars, you want to stay fast and loose. You don't want to get filled up. That's why I drink Lite Beer from Miller. It has a third less calories than their regular beer and it's less filling. Plus, the taste is great. And even though a lot people don't think pool is strenuous, let me tell you something. You can work up a real good thirst even when you're just showing off.
The summary of the commercial from the archives is as follows:
In this commercial for Miller Lite, professional pool player Steve Mizerak demonstrates some fancy shots at the pool table. He explains that he drinks Lite Beer from Miller to stay fast and loose, even when he's just showing off. Slogan (supered): "Lite Beer from Miller. Everything you always wanted in a beer. And less."
"The Greatest Lite Beer Pool Shoot-out" with Steve Mizerak for a Miller Lite TV Commercial
(better known as the Miller Lite "Practice, practice, practice")
Steve Mizerak Miller Lite "Merry Christmas from Miller Lite" TV Commerical
Here are a few photos of Steve from the ad campaign, which was originally posted in Billiards Digest.
And here is some back-story about the commercial series from Robert Byrne, as told to him by Mizerak and others:
When the decision was made to make a Lite ad featuring a pool player, Mizerak was chosen over several other pros because he was able to project an appealing personality, and, rumor has it, the company felt he looked like a beer drinker. (At the time he weighed 225 lbs.; hefty, but not over the line for his 6'1" frame.) In his 1990 book, "Steve Mizerak's Complete Book of Pool," he stated that when he learned that he had been chosen to star in the original commercial in 1976, "I literally danced around the living room."
The commercial took nine hours to film and required 191 takes. Sometimes the timing between the words and the pool shots wasn't quite right, or Mizerak would muff a line, or somebody would sneeze, or a light would fail, or a door would slam, or the cue ball would end up in the wrong place, or a ball wouldn't drop. It took all of his powers of concentration and stamina to keep at it and stay upbeat until he and the crew had something that was both technically perfect and utterly charming. The commercial was brilliant and a huge success, running seemingly constantly over the course of a year or two. It made him a pool icon for life. Mizerak also became a member of the pitchman fraternity known as the Lite Beer All-Stars, a group of active and retired pro athletes from various sports who appeared in Miller ads. They often made public appearances, and Mizerak in particular was always in demand for exhibitions.
Full List of Miller Lite Beer Commercials from 1970s and 1980s
Of course there are more, but these list the ones with Mizerak.
1991 - Academy Awards
1988 - Alumni Board Meeting
1987 - Alumni Portrait
1986 - "The Case of the Missing Case" - Didn't see Steve in this one, but he probably was there in the background.
1986 - Baseball
1985 - Alumni Golf Commercial "The First Lite Beer Open"
1984 - Camping
1983 - Baseball
1982 - "First Lite Beer Bowling Tournament" - Steve Mizerak's short scene at 00:00:25 shows him getting in stance to bowl holding a bowling-ball-sized 8 ball, saying "8 ball, in the pocket"
1982 - "First Annual Lite Beer Banquet" - Steve Mizerak is in this one for a split-second near the end saying his famous line "just showing off".
Part of the classic Lite Beer from Miller series of TV commercials from the late 1970s, this one brings many beloved figures together for a banquet, including a slim Rodney Dangerfield, Bubba Smith, Ben Davidson, Steve Mizerak and many more.
1981 - Miller Lite Christmas Commercial - "Merry Christmas from Miller Lite", with John Madden, Bubba Smith, Billy Martin, Steve Mizerak, and others.
1980 - "The Greatest Lite Beer Pool Shoot-out" but better known as the Miller Lite "Practice, practice, practice" commercial.
1979 - "Just Showing Off" Miller Lite commercial with Steve Mizerak
1978 - "Battle of the Big Guys" - Tug of War - the first one, and apparently it was pulled after only being shown 3 or so times nationally.