Tonight you will hear from the man President Donald Trump appointed as his 2020 re-election campaign manager. His name is Brad Parscale, and he got the job because - as we first reported in October - Parscale was the president's secret weapon in his 2016 run for the White House.

Brad Parscale CBS News

42-year-old Parscale was one of the campaign's top decision-makers, operating largely out of public view. He was hired to run the digital team, but over time he came to oversee advertising, data collection and much of the fund-raising. He says his main task was competing with the Clinton Campaign's huge advantage in money and tv ads. What he decided to do was turn to social media, most importantly to Facebook.

"I understood early that Facebook was how Donald Trump was going to win. Twitter is how he talked to the people. Facebook was going to be how he won."

Brad Parscale: I understood early that Facebook was how Donald Trump was going to win. Twitter is how he talked to the people. Facebook was going to be how he won.

Lesley Stahl: And Facebook IS how he won.

Brad Parscale: I think so. I think Donald Trump won, but I think Facebook was the method -- it was the highway in which his car drove on.

Brad Parscale Donald J. Trump campaign

And Brad Parscale was in the driver's seat. In the beginning of the campaign he worked alone at home in San Antonio, but by the end he had 100 people reporting to him. One of his main jobs was to send out carefully-tailored, low-cost digital ads to millions of people.

Lesley Stahl: And these were ads on Facebook?

Brad Parscale: Facebook, we did 'em on Twitter, Google search, other platforms. Facebook was the 500-pound gorilla, 80 percent of the budget kind of thing.

Facebook's advertising technology helped President Obama in 2012, but today Facebook offers something far more precise and sophisticated. While the president tweeted in the past that "Facebook was always anti-Trump," Parscale relied heavily on the company. Particularly on its cutting-edge targeting tools.

Lesley Stahl: One of the best things Facebook did for you, I heard, was penetrate the rural vote. Is that correct?

Brad Parscale Donald J. Trump campaign

Brad Parscale: Yeah. So Facebook now lets you get to places and places possibly that you would never go with TV ads. Now, I can find, you know, 15 people in the Florida Panhandle that I would never buy a TV commercial for. And, we took opportunities that I think the other side didn't.

Lesley Stahl: Like what?

Brad Parscale: Well, we had our-- their staff embedded inside our offices.

Lesley Stahl: What?

Brad Parscale: Yeah, Facebook employees would show up for work every day in our offices.

Lesley Stahl: Whoa, wait a minute. Facebook employees showed up at the Trump headquarters --

Brad Parscale: Google employees, and Twitter employees.

Lesley Stahl: They were embedded in your campaign?

Brad Parscale: I mean, like, they were there multiple days a week, three, four days a week, two days week, five days a week --

Lesley Stahl: What were they doing inside? I mean --

Brad Parscale: Helping teach us how to use their platform. I wanna get --

Lesley Stahl: Helping him get elected?

Brad Parscale: I asked each one of them by email, I wanna know every, single secret button, click, technology you have. "I wanna know everything you would tell Hillary's campaign plus some. And I want your people here to teach me how to use it."

Lesley Stahl: Inside?

Brad Parscale: Yeah, I want 'em sittin' right next to us --

Lesley Stahl: How do you know they weren't Trojan Horses?

Brad Parscale: 'Cause I'd ask 'em to be Republicans, and I'd -- we'd talk to 'em.

Lesley Stahl: Oh, you only wanted Republicans?

Brad Parscale: I wanted people who support Donald Trump from their companies.

Lesley Stahl: And that's what you got?

Brad Parscale: Yeah. They already have divisions set up that way.

Lesley Stahl: What do you mean?

Brad Parscale: They already have groups of people in their political divisions that are Republican and Democrat.

Lesley Stahl: You're kidding?

Brad Parscale: Yeah, they're businesses, they are publicly traded companies with stock price.

Lesley Stahl: Did Hillary's campaign have someone embedded --

Brad Parscale: I had heard that they didn't accept any of their offers.

Lesley Stahl: So you're saying Facebook and the others offered an embed, and they said no.

Brad Parscale: That's what I've heard.

People in the Clinton campaign confirmed that the offer was made and turned down. Facebook told us in a statement:

Facebook's statement to 60 Minutes CBS News

"...for candidates across the political spectrum, Facebook offers the same levels of support in key moments to help campaigns understand how best to use the platform."

And indeed, both campaigns used Facebook's technology extensively to reach out to potential voters. Parscale said the Trump campaign used the technology to microtarget on a scale never seen before -- and to customize their ads for individual voters.

Brad Parscale: We were making hundreds of thousands of 'em.

Lesley Stahl: You make 100,000 ads.

Brad Parscale: Programmatically. In one day. In one day.

Lesley Stahl: So 100,000 different ads every day?

Brad Parscale: Average day 50-60 thousands ads.

Donald J. Trump campaign ads CBS News

This was all automated.

Brad Parscale: Changing language, words, colors, changing things because certain people like a green button better than a blue button. Some people like the word "donate" or "contribute."

Lesley Stahl: So how would you know ... let's say I like a green button. How do you know I'd only like a green button?

Brad Parscale: Because I'd give you the red, blue buttons, you never click on 'em.

Parscale showed us how they tested: by sending out multiple versions of the same ad with only subtle differences.

Brad Parscale: Here we have an American flag, here we have a face of Hillary. Different colors, the blues, different messages above.

Lesley Stahl: So you'd send two identical ads with different colors?

Brad Parscale: Maybe thousands.

Lesley Stahl: You'd send THOUSAND of ads with different colors?

Brad Parscale: Different colors. What it is is: what can make people react? What catches their attention? Remember, there's so much noise on your phone. You know, or on your desktop. What is it that makes it go: Poof! "I'm gonna stop and look."

Three campaign ads with similar appearances but different messages. CBS News

To get people to stop and look, he crafted different messages for different people -- so that you only got ads about the issues you cared about most. He showed us three ads that looked alike.

Brad Parscale: It's pretty much the identical design. Positive coloring. Different message.

Lesley Stahl: This is one is tax, this one is childcare, this one is energy.

Brad Parscale: They were all targeted to different users of whatever platform, in this case it was Facebook.

Sent out to different people. And it could be each other's next-door neighbors…all in Ohio.

Lesley Stahl: This one person at 11 Elm Street gets this one and 13 Elm Street gets that one.

Brad Parscale: Yup, yup.

Parscale took some heat for taking micro targeting too far because he hired Cambridge Analytica. The company, now defunct, used so-called psycho-graphics that micro-target ads based on personality. For instance, an extrovert would get one kind of message, a neurotic person another. It's controversial because of its Orwellian overtones.

Brad Parscale Donald J. Trump Campaign

After Trump won, Cambridge Analytica said it was key to the victory. But Parscale insists he never used psychographics. He said it doesn't work.

Lesley Stahl: So you didn't use it because you didn't think it really worked, as opposed to you didn't use it because you thought it was wrong that it was manipulative or sinister, or something like that.

Brad Parscale: No, I don't believe it's sinister.

Lesley Stahl: No. OK, you just don't think it works.

Brad Parscale: No, I just don't think it works.

Parscale's title was digital director, but by the end of the campaign his portfolio grew. He oversaw data collection, polling, advertising both online and on TV, and significantly digital fund raising. By adding donation buttons for people to click on in the online ads, he was able to bring in a record $240 million in small donations.

Lesley Stahl: How many presidential campaigns had you worked on before this one?

Brad Parscale: Zero.

Lesley Stahl: Your wife has a wonderful expression about you being thrown into this.

Brad Parscale: Yeah. She said that I was thrown into the Super Bowl, never played a game and won.

Lesley Stahl: That's what it sounds like.

It's made him a local hero back home in Kansas. He grew up in Topeka, playing basketball -- he's 6 foot 8. After briefly working at a tech company in California, he moved to San Antonio, Texas, and became a marketer. He taught himself to code, opened a small web-design business and went looking for customers.

Brad Parscale: I started tapping shoulders at a bookstore asking people if they needed a website, when they were buying books on web design.

Lesley Stahl: Yeah, but what-- you're hanging around at a bookstore?

Brad Parscale: Yeah, a Border's.

Lesley Stahl: You're hanging around at Border's and say, "Can you hire me?"

Brad Parscale: Yeah.

Lesley Stahl: Come-on.

Brad Parscale: Yeah.

Lesley Stahl: So how did you get involved with the Trump people?

Brad Parscale: I was sitting at IHOP and I got an email. I was eating a ham and cheese omelet. I was. I get an email and I open it up and it says -- "This is Kathy K. from the Trump Org -- can you please call me?" That's it --

Lesley Stahl: Outta nowhere?

Brad Parscale: Outta nowhere.

Six years ago she was looking for someone to design a website for a Trump real estate project. Parscale bid lowest, got the job, and soon many more followed: websites for Eric's foundation, Melania's skincare line, the family's wineries. Then, in early 2015, came another life-changing email:

Brad Parscale: It said "Donald Trump is thinking about running for president. We need a website in two days." So I wrote back, I said, "Yeah, I'll do it for $1,500."

Lesley Stahl: $1,500?

Brad Parscale: Yeah. And by the end, it was $94 million.

$94 million is what his company was paid. Much of it was spent on things like buying ads. Parscale learned very fast on the job, with the help of the Republican National Committee. They had amassed a giant database to identify the issues people cared about, and predict how nearly 200 million Americans would vote.

One reason Parscale thinks President Trump won is because of an issue the RNC database honed in on that he says the Clinton campaign missed:

Lesley Stahl: Infrastructure.

Brad Parscale: Infrastructure. It was voters in the rust belt that cared about their roads being rebuilt, their highways, their bridges. They felt like the world was crumbling. So I started making ads that would show the bridge crumbling. You know, that's microtargeting them. Because I can find the 1,500 people in one town that care about infrastructure. Now, that might be a voter that normally votes Democrat.

While he tried to persuade Democrats to vote for Mr. Trump -- the campaign was accused, in a Businessweek article, of trying to suppress the vote of "idealistic white liberals, young women and African Americans," a charge he denies.

Lesley Stahl: Did you micro target by race?

Brad Parscale: No we did not. Not at all.

Lesley Stahl: Never?

Brad Parscale: Nope.

Lesley Stahl: Did you post hateful images?

Brad Parscale: I don't believe so.

Lesley Stahl: The candidate Trump was never shy about pushing buttons, about pushing prejudices. He used what most people would consider offensive language sometimes.

Brad Parscale: I don't think the math said that most people saw it as offensive. I think a small group of people saw it as offensive, who have a lot of power.

Lesley Stahl: But you did mirror him?

Brad Parscale: We mirrored certain things that he would say, mainly things he said in rallies.

Many of the messages he sent out were what's known as dark ads. They're called dark because they're microtargeted to individual users who are the only ones who see them. Unless they choose to share them – they disappear.

Lesley Stahl: Can you say anything you want in those dark ads? They're really not transparent?

Brad Parscale: No, because if I said something crazy in those, they would share a million times, it would be all over.

Lesley Stahl: So if you said something that appealed to racists?

Brad Parscale: Oh, it would be everywhere.

But some dark ads flew under the radar, like ones sent out, we now know, by the Russians in their attempt to influence our election. These were separate from the posts the Russians reportedly sent of fake news stories that made Clinton look bad. The ads -- on divisive issues -- were spread using Facebook tools similar to the ones Parscale and the Clinton campaign used.

Lesley Stahl: Facebook has admitted that the Russians spent $100,000 -- at least $100,000 -- on ads to influence the U.S. campaign. Does that bother you?

Brad Parscale: Yeah, I would not want a foreign entity to meddle in our election; you know, a government. Yeah, I mean, I wouldn't want that; I'm American.

But the question is: did the Trump campaign collude with the Russians -- and as the digital director, was Parscale involved?

Brad Parscale: I think it's a joke. Like, at least for my part in it.

Lesley Stahl: Very few people think it's a joke.

Brad Parscale: I think it's a joke when they involve myself. 'Cause I know my own activities, and I know the activities of this campaign. I was there. It's just a farce.

Lesley Stahl: It's a farce that you colluded with the Russians?

Brad Parscale: Yeah. It's just a joke.

What about what happened on Twitter? Which was flooded with pro-Trump tweets generated by robots, or bots.

Lesley Stahl: Did you have a hand in generating these bots --

Brad Parscale: I had nothing to do with bots. I don't think bots work.

Lesley Stahl: You were called the king of the bots.

Brad Parscale: I know. It's ridiculous. It's just the craziest thing ever. No one on our team ever sat down with me and said, "Brad, we should make bots."

Lesley Stahl: But if-- if you see that there are hundreds of thousands of bots floating around with pro-Trump messages, somebody generated it. Where would it come from?

Brad Parscale: I would imagine there were people, everyday people in America, who thought they were trying to help. I don't know.

Lesley Stahl: If the bots came from the Russians, would you know?

Brad Parscale: Nah.

Lesley Stahl: Do you think it might have?

Brad Parscale: No idea.

Lesley Stahl: Could it have?

Brad Parscale: Could be from anybody in the world.

Both the House and Senate intelligence committees looking into Russia's meddling met Parscale for lengthy closed door sessions.

Parscale told us the Russian plotline is pushed by liberals who think they lost because he cheated. The irony, he says, is that it wasn't a foreign entity helping the campaign, but left-leaning American companies like Twitter, Google, and above all Facebook.

Brad Parscale: These social platforms are all invented by very liberal people on the West and East Coast, and we figure out how to use it to push conservative values. I don't think they ever thought that would happen. I would say the number one thing that people come up to me is, like, "I just never thought Republicans would be the ones to figure out how to use all this."

Lesley Stahl: So a liberal invents all this stuff and a conservative in the Middle-West figures out how to use it?

Brad Parscale: And I think we used it better than anyone ever had in history.

Facing mounting criticism over dark ads with political content, Facebook is in the process of updating its policies, including doing a better job disclosing who's paying for these ads, and creating a central depository of all the ads, so anyone can scrutinize their content.

Produced by Shachar Bar-On. Natalie Jimenez Peel, associate producer.