Al's cigar was the idea of Dean Stockwell, who said it was "a good way to get free cigars for five years".
The series came close to being canceled in its third season due to low ratings. However, a letter-writing campaign helped save the series, enabling it to continue for two more years.
In the scenes where Sam Beckett is seeing someone else's reflection in the mirror these scenes are shot on a dual set using a clear glass mirror in which Scott Bakula would stand on one side and the actor or actress he'd leap into would stand on the other side.
Scott Bakula ad libs the line "Oh, boy!" at the start of the first episode. The producer liked it so much that it became the signature final line of each episode, as Sam finds himself in a new body.
Scott Bakula was the first actor cast and, thus, was asked to read with actors under consideration for the role of Al Calavicci. Bakula immediately felt a connection with Dean Stockwell during his audition and lobbied the producers to cast him as Al.