Aired: 1987-94 Syndicated
DAD: Worf (Michael Dorn) 
DAD’S JOB: Security Officer, USS Enterprise
KIDS: Alexander Rozhenko (Brian Bonsall)
WHERE’S MOM?: Assassinated by rival Klingon House.
STAND-IN "MOM": Worf’s step-parents, and maybe Counselor Troi
Another "just barely qualifies" series. Worf really didn’t get to be a TV Single Dad until the third season of the show, but he was a TV Single Dad for the majority of the run of the series, so he’s In The Club. He was also one of the more reluctant TV Single Dads. In fact, there probably isn’t any other TV Single Dad who resisted the role more than Worf. My nearest guess would be the dad on Silver Spoons.
Update: Alert Viewer Carlos points out – "Worf’s mate Ambassador K’Ehleyr (played by Suzie Plakson aka Paul Reiser’s ‘sister-in-law’ in Mad About You.), was assassinated by a rival Klingon house." Thanks, Carlos!