One of your first encounters with San Francisco city government was when you fought against the demolition of an S.R.O. hotel.

Four chains of people wrapped their arms around the block to prevent its destruction. Horses came in, nightsticks, everything. We never allowed the development to happen, by the way.

You were a housing rights advocate in a city with strong tenants’ rights.

I used to brag that I can hold up any eviction — even if the landlord had legal rights, I could hold it up for a year.

And now the redevelopment of a part of downtown called Mid-Market, spurred by the so-called Twitter tax break, is a centerpiece of your mayoralty. What changed?

If you looked at Mid-Market five years ago, all you saw were vacant buildings, abandoned storefronts, five or six strip joints and bars at night. All seedy, no lights, check-cashing centers, that kind of condition. Twitter wanted to move, and they told me: we’re going to have to leave the city because you have this payroll tax that punishes us for growing. So we created a tax break for a certain part of the city. Now people are competing for the vacancies.

For its side of the community-benefit agreement that came with the tax break, Twitter gives out promoted tweets to local nonprofits.

What I learned with tech companies is I gotta give people room to experiment, and also to make what might later on be a mistake. This is the attitude I want to build within San Francisco — give some time to the tech community. At the end of the day, tech workers are not robots: they feel, they think, they have values.