To fund PSI, he started a for-profit condom company. (When the company started out, it was still illegal to sell condoms via mail order in the US, but they did it anyway as profitable civil disobedience.) They later expanded into sex toys and "erotica". I take it that his chosen industry is one reason he's not famous.
Harvey used profits from Adam & Eve [the largest sex toy company in the US] to supplement support from international donors to protect millions of poor couples from unwanted pregnancies and HIV infections. In 2019, DKT International provided contraceptive protection to 49 million couples.
"We tried to get our customers to buy leisure wear, shipbuilding kits, belt buckles, model airplanes, but they just yawned at that stuff. Every time we put something with erotic appeal in the catalog, the [phone] bells would ring."
In 1986, Adam & Eve's offices in Carrboro, North Carolina were raided by 37 armed local law enforcement agents. For the next six years, Harvey defended himself against multiple indictments for obscenity...
PSI were Givewell's initial top charity, for their very early and wide distribution of oral rehydration therapy (though GW's cost-benefit process was notably weak at that point, as Karnofsky concedes here). The Life You Can Save still has an (uncritical?) active page for them. They also provide other interventions which are often great (voluntary male circumcision for HIV prevention, malaria nets, maybe radio education). They have a homegrown evaluation method which I find kinda empty.
An interesting angle is their many legal challenges. Their successes include opening up the contraception market and guaranteeing access for American young people; briefly having the global gag order on promoting abortion removed; and an eventually successful fight to allow NGOs to be neutral on sex work. Law is a giant slow steamroller, but it is involved in many lasting improvements to society, and these victories in particular seem well worth the cost.
DKT were briefly considered by Givewell in 2008 but didn't stand out. Their own numbers put some emphasis on inputs (# condoms and kits sold), and I'm not sure where their output estimates come from (last year, "11 million pregnancies averted" and "49,000 maternal deaths averted"). They use an interesting narrow unit, the Couple-Year of Protection (contraceptive bang for your buck). This was probably an advanced method when it was developed in the 70s.
Both organisations are notable for selling their products at cost rather than distributing them for free, under the assumption of inelastic demand, that recipients get to vote with their wallets, plus maybe increased use for things they themselves pay for. Clearly it also produces short-term cost savings. I think this idea was in favour in development economics in the 2000s but haven't heard much about it since. The obvious objection is that they're crowding out local production and sales. (But this wouldn't have been true in the 1970s.) I don't hear much about social enterprises in EA, possibly for good reasons.
Overall I don't know about family planning as a cause. But it's a perennial top-10 cause in ordinary international development, and after more than a decade in the shade it has returned to EA attention.
Regardless, PSI was an early adopter of many of the most effective global health interventions. (This was mostly after Harvey's tenure as president, so model his Shapley contribution as you will.)
I'm not going to estimate Harvey's lifetime impact, but I hope someone does.
Harvey's path - from development worker, to entrepreneur, to philanthropist, to key player in blockbuster legal cases - is an example of someone thinking seriously about routes to impact, of pulling off a huge career pivot, of method neutrality if not cause neutrality, and - unlike us - of managing this intellectual and organisational feat almost alone.
Even discounting the perverse degrowth strand, and the perverse authoritarian strand, neither of which I take Harvey to belong to.
Which might explain the lack of EA attention: even ignoring funky population ethics questions, it doesn't seem very neglected, and we have Harvey and Black and half of the international development industry to thank for that.