Sackett was born in the United States, and studied at Touro College in New York City. He was educated in both Talmudic scholarship and secular academic subjects. He had been involved in Jewish youth work, and in Jewish educational outreach to secular Jews, some of whom became baal teshuvas ("returnees to Judaism") under his tutelage. He worked in Wall Street's Financial District before making Aliyah to Israel and settling in the West Bank in 1990.
Sackett had been a member of the JDL in the 1970s, and a loyal follower of Kach leader Rabbi Meir Kahane in the United States. Sackett eventually followed Kahane to Israel, where he joined Kach and, later, Kahane Chai. And became the director of Kahane Chai. After Feiglin's election to the Knesset in 2013, Sackett authored an article on the Manhigut Yehudit website rejecting calls from supporters that he and Feiglin renounce Kahane. He co-founded Zo Artzeinu with Moshe Feiglin in 1993.
While Sackett was a close friend of Kahane's son, Rabbi Binyamin Ze'ev Kahane, he disagreed with the younger Kahane's tactics. Sackett and Feiglin shared some of Meir Kahane's goals, such as creating a more Jewish and secure Israel (and, like Kahane, advocated the "transfer" of Arabs outside the country), but wished to achieve them via non-violent methods.
Sackett worked as Manhigut's International Director. When Feiglin left Likud and created Zehut Sackett joined him and was chosen 12th on the party list for the April 2019 elections in which the party did not pass the electoral threshold. In the following September 2019 elections he was placed in the 15th and final place in Zehut's candidate list. The party forgoed the candidiacy before the elections took place.
- JPost Archived 2011-04-15 at the Wayback Machine Kahane, wife killed by terrorists by Margot Dudkevitch
- Jewish news weekly of Northern California Right-wingers view themselves as conspiracy victims by Larry Derfner
- Richard J. Chasdi (2002) Tapestry of Terror: A Portrait of Middle East Terrorism, 1994-1999 Lexington Books, ISBN 0-7391-0355-5 p 316
- Sackett, Schmuel. "An Answer to Plaut from Feiglin's Kahanist". Manhigut Yehudit. Archived from the original on 23 November 2013. Retrieved 16 February 2013.