George Christopher, the last GOP Mayor, (1956-64), was a liberal, but highly pro-development (along the lines of Dianne Feinstein). Perhaps a little too strongly pro-development, since Christopher was reviled for allowing the demolition of a beautiful movie theater, the old Fox, still talked about with anger today (I consider myself a preservationist, so that bugs me as well).
Christopher was the GOP establishment choice for Governor in 1966 to face Pat Brown (at that point, a SF Mayor hadn't been elected Governor since Republican Sunny Jim Rolph in 1930, who had served as Mayor for a record-breaking 19 years). It's possible, but not a given Christopher could've beaten Brown, and there wasn't much of an ideological difference between the two. Ronald Reagan saw his opening here and beat Christopher in an upset in the primary, by an embarrassing landslide of 65-31%. Given that margin, I had reason to doubt that Christopher would've been particularly formidable in the general.
The next 2 Mayors after Christopher hailed from the pro-development establishment of the city, that being Congressman Jack Shelley and Joe Alioto. Shelley probably wished he'd remained in Congress when he had to deal with the freak show invasion of hippies and the Summer of Love (a lot of the ones that came in were teens and children who had run away from home from all over the country, and were all over the streets, many on drugs - a total nightmare to deal with, for the cops, and the officials). Shelley quit after a single term (1964-68).
The closest last race with a clear-cut Conservative Republican, as I cited, was the 1975 race between Moscone and John J. Barbagelata, a Supervisor. Barbagelata might very well have won had it not been for Jim Jones's footsoldiers who carried Moscone to a narrow victory (a swing of 2,000 votes would've carried it for the Republican). Moscone was effectively the first non-establishment Mayor in the modern era, a real swing to the hard left (I found it remarkable he even made it to Majority Leader in the Senate as a member of the radical faction, since there were a lot more non-moonbat Dems in those days).
The last semi-Conservative Mayor was probably Frank Jordan (1992-96). I was in SF at the time of the very ugly battle between him and incumbent Mayor Art Agnos in late '91. Agnos, Feinstein's successor in his first term, couldn't get a handle on the ultra-aggressive homeless problem. Jordan was the Police Chief. He got in and dealt with it, but the predictably ultraleft residents felt BAD for trying to clean up the mess and being "mean."
Jordan faced reelection in '95 against Willie Brown, who had effectively lost his power in the Assembly after term limits, but had spent that entire year making a monkey out of the new GOP Assembly Majority, keeping them tied up in knots with puppet RINO Speakers he kept backing until he finally exited (we only had 1 year of real control of the body with a full caucus-approved non-RINO Speaker, a real shame). Anyway, Jordan, in one of the most bizarre stunts of a politico in recent memory, was persuaded to hop into a shower, butt-nekkid, with 2 local radio hosts, all in an effort to shore up his support (with whom ?). It backfired and Jordan lost by a wide 57-43% to Willie.
