During his eleven years at ABC News, Tessem was a producer/director for the news magazine, 20/20, as well as for the critically-acclaimed primetime historical series, Our World. Tessem was also one of the producers of ABC's notable three-hour biography of Franklin Roosevelt. FDR, which aired in 1982, won nearly every major documentary television award that year.

In 1981, while at 20/20, Tessem's story on the twentieth anniversary of the Berlin Wall won the Emmy award in the News and Documentary category. It featured the first television appearance of many of the heroic individuals who made dramatic escape attempts during the first days of the wall's existence.

Tessem took time out from ABC in 1984 to produce and direct two award-winning documentaries for PBS's Smithsonian World series: Heroes and the Test of Time, and On the Shoulders of Giants, which were both notable for their lush photography a hallmark of Tessem's work and a reflection of his earlier years as a cinematographer.

In 1987, Tessem joined Linda Ellerbee in forming Lucky Duck Productions, which now operates as a full service video production company, where the two team up to executive produce programming for network, syndication, cable and public television.