Cissy! Yes, that was it. Thanks.
Holy shit! Still working.
Tiffani Thiessen from Saved by the Bell.
Farah Forke from Wings.
ETA. From movies, I had a huge crush on Ami Dolenz in Miracle Beach.
Exactly why I specified before twelve. Maybe not babysitter, but someone you get non-sexual tinglies about seeing on in TV or movies. You know you like seeing them and get the tinglies, but don’t really know why.
Susan Hampshire played Joy Adamson in the sequel to Born Free, Living Free when I was twelve and I had tiny crush of Virginia McKenna in the original, but a bigger crush on Susan Hampshire. At the time it didn’t really click that it was different actress, I just knew she got prettier.
Seeing them on TV and movies was a much bigger thing in the '60’s/70’s since there was no replaying that moment. Once it was done, you had to hope for reruns or pay to see the movie again.
This is straying from the OP a little,
We had this station here a few years ago that played old TV shows all the time. It was called Antenna TV. There was a show from before my time that I caught a few times . It was a father who, I think was widowed and had a teen daughter. The dad seemed to have a very active dating life and all the actresses that played his dates were way younger than him, not much older than the daughter (Seemingly. Kind of half creepy and half “Yeah, go get 'em old dude”) and every one was very, very attractive. Anyone know the show I’m thinking of? All the times I saw this show I had the sound off on the TV and was listening to something else so can’t offer any other clues.
Bachelor Father, starring John Forsythe of Dynasty fame?
Oh, wait: She was his neice, not his daughter…
That’s the show. Should have recognized John Forsythe. 1957 (series premier) was the year I was born. So wasn’t crushing on anybody yet.
Also liked Blair from Facts of life. Lisa Whelchel
they made Andy Griffith a widower because they thought there would be more plots if he was not married but they did not think people would accept him as being divorced.
It was the first one that came to my mind. The last time I saw it was probably in 1961 or '62.
Forsythe played a widowed dad ten years later in To Rome with Love.
Yes, and almost all the shows about widowed dads had “mother” substitutes that were obviously not sex objects: Andy had “Aunt Bea,” and Fred MacMurray had “Bub” (William Frawley) and “Uncle Charley” (William Demarest) on My Three Sons. Jed Clampett had “Granny” on The Beverly Hillbillies.
In a reversal of the formula, widow Bea Benadaret had “Uncle Joe” (Edgar Buchanon) on Petticoat Junction.
About the only widowed dad without a mother figure I can think of was Don Porter on Gidget.
Here’s a list of TV single dads iof the '50s and '60s:
I guess the widow(er) card was big, back in the day. Brady Bunch, anyone?
I mean, if you tell us Mike is a widower but you don’t tell us about Carol…? I guess the girls never talked to, pined for, or had any dealings with their father. Because you know, there were no other ways for a woman to have three daughters in those days.
From that era, let’s don’t forget Karen Valentine. Check out the dress!
Karen Valentine…totally forgot about her. Yeah, probably crushed on her a little.
I was an extra in a movie starring Kathy Garver a few years ago. I did not actually meet her, but I saw her interacting with cast, crew, and other extras. Always smiling and laughing. She seemed like a lovely person.
Were you seeing that as a kid? Because it has a lot of nudity.
I liked Jo.
I may have slightly fudged the OPs requested timeline. I was 14 when I watched it.
Just discovered this thread.
Yeah, I liked Karen Valentine in Room 222 and Susan Dey in The Partridge Family a lot, and that was even when I still thought most girls had cooties.
Courtney Cox on Family Ties sure caught my attention.
Once I got hooked on sf, I took, er, particular notice of Nichelle Nichols on Star Trek, Maren Jensen on Battlestar Galactica, and Erin Gray on Buck Rogers. Mrowrrrr.
Not too long ago, I saw June Lockhart in T-Men (1947) and barely recognized her. She was incredibly hot back then, much more than on either Lassie or Petticoat Junction.
I felt the same way about Anne Baxter when I saw her in The Magnificent Ambersons (1942) and Angel on My Shoulder (1946).
Shirley Jones I never really appreciated until I saw her recently in reruns of The Partridge Family. She definitely stacked up (so to speak) to Susan Dey! 
And how could I forget Jaclyn Smith on Charlie’s Angels? I even had a poster of her in my room. Le sigh.