Born in Chinook, Montana, Blackstone served in the United States. Navy during World World War II, and was honorably discharged. In 1949, he became a San Francisco police officer and was a pioneer of what is now called community policing. In 1962, he was designated as the department"s first liaison officer with the "homophile community," as it was then called.
Blackstone worked within the police department to change policy and procedures directed against the LGBT community, such as entrapment of gay men in public restrooms.
Throughout the 1960s and early 1970s, Blackstone worked closely with local LGBT activist groups such as the Mattachine Society, Daughters of Bilitis, the Vanguard gay youth group, the National Transsexual Counseling Unit, and the Council on Religion and the Homosexual. Blackstone even took up a collection at his church to buy hormones for transgender people, at a time when city-funded health clinics would not provide hormones to them.
Blackstone was also involved in many other church and community activities, and taught community policing courses at the College of Marin. At his retirement dinner in 1975, he was saluted by LGBT community leaders for his advocacy and support.
In 2005, an interview with Blackstone was featured in Screaming Queens, a documentary about the 1966 Compton"s Cafeteria riot.
According to one source,
At the 2005 world premiere at the Castro Theater, Blackstone received a standing ovation from a sold-out crowd of more than 1000 people, when he answered an audience member"s question. Asked why, as a straight man, he had worked so hard on behalf of LGBT rights, he said, "Because my religion teaches me to love everybody."
In June, 2006 Blackstone received commendations for his longtime advocacy work from the California State Senate, the California State Assembly, the San Francisco Police Commission, and the San Francisco Human Rights Commission. Blackstone died of a stroke later that year, just a month short of his 82nd birthday.