He made the short documentary film Village of Hope about a leper colony in Liberia.

Alexander produced musical shorts, such as Jivin' in Bebop (featuring Dizzy Gillespie), Burlesque in Harlem, and Open the Door, Richard (whose theme later became a hit record).

Over the next 18 years, he produced a series of highly-praised documentaries concerning the new states emerging from colonialism in Africa.

In 1960, the American ABC television network broadcast a twelve-part documentary by Alexander concerning the new African states.

Wealth in Wood, another of Alexander's documentaries, was given the United Nations Award at the Madrid International Film Festival in 1967.

[citation needed] Despite its big budget and all-star cast, which included Richard Burton, Lola Falana, and Lee Marvin, The Klansman was Alexander's least successful film.