Dunham was an American actor, who made his living in Tokyo, Japan. He is best known for his role as Antonio, Emperor of Seatopia in Godzilla vs. Megalon (1973) as well as his role as Mark Jackson, in Dogora or Dagora the Space Monster (1964). Dunham was living in Japan, during the Golden Age of Cinema. He was cast in many films between 1961-1974, usually as a heavy. He worked for Toho Studios, best known for their Godzilla films. Dunham was cast in their movies such as Mothra (1961), Dogora or Dagora the Space Monster (1964), The Face of Another (1966), Godzilla vs. Megalon (1973), and ESPY or Esupai (1974). He also acted in films such as Marines Let's Go (1961), Greed in Broad Daylight (1961), Operation Diamond (1962), Woman in the Dunes (1964), A Flight from Ashiya (1964), with actor Yul Brynner, The Green Slime (1969), The Little Adventurer (1973), with British child actor, Mark Lester. In 1966, Dunham wrote, directed, and helped produce a movie with his friend, Cliff Harrington. It was called The Time Travelers, which starred then child actress Linda Purl. Dunham credits starting Linda Purl's acting career, as this was her first film. (Linda Purl was 10-years-old at the time. She was born in the United States but was raised in Japan.) As far as what made Dunham stand out from other Caucasian actors in Japan at the time, was that he spoke fluent Japanese.

Dunham was born in Portland, Maine. He grew up in Wellesley Hills, Massachusetts. Born to an affluent family, his parents were Earl and Charlotte Grace(Dean)Dunham. He has an older sister named Patricia June(Dunham)Oburchay. His paternal grandparents were William and Clara Dunham, of Nova Scotia. His maternal grandfather was Henry Ellsworth Dean and his maternal grandmother was Bertha May(Chadbourne)Dean, of Worcester, Massachusetts. His maternal great grandparents were Alonzo and Almira Chadbourne, of Portland, Maine.

Dunham graduated from a private school called Noble and Greenough School, in Dedham, Massachusetts, in 1949. He was later accepted into Williams College, in Williamstown, Massachusetts. While at William's College, he played for the J.V. squash and lacrosse teams. He belonged to the Delta Kapa Epsilon fraternity. He graduated from Williams College in 1953, with his Bachelor's degree in Art History.

After graduating from Williams College, Dunham joined the United States Marine Corps. After graduating from the U.S. Marine Corps' Officer Candidate School, he was sent to Yokohama, Japan in 1953. He served for two years as a 2nd Lieutenant of the Military Police. After being honorably discharged from the U.S. Marine Corps, he returned to home to to work for his father's Pontiac dealership. After only nine months, he went back to Tokyo, Japan. Later, he attended correspondence school, to learn how to speak Japanese. In the late 1950s, he opened up his own import and export business called Pan Commercial Ltd., where he exported shoes. He was one of the top 5 exporters of shoes, in Japan.

In the early 1960s, Dunham worked as a coordinator for Hino Motors. He was introduced to American race car designer and race car driver Pete Brock, through Hino Motors. (Brock had designed the Hino Contessa 900GT and the Hino Contessa 1300, for Hino Motors. In addition, he designed the Shelby Daytona Cobra Coupe for Carroll Shelby at Shelby American.) Dunham had previous experience, racing cars on the upstate New York's dirt racing circuit. Both Dunham and Brock started racing the Hino Contessa in both Del Mar and Riverside, California, and were gaining a lot of attention with this compact, yet speedy car. On October 10, 1964, Dunham raced the Hino Contessa 1300 GT at the Riverside GP (California) and placed second in G class. On November 1,1964, he won first place at Willow Springs Hill climb (California), in the 1100cc class, with Peter Brock placing second. Then, in November 22, 1964, Dunham raced the Hino 900 GT and got 1st in class and 6th in total at the Del Mar race. Unfortunately for both Dunham and Brock, Hino was bought out by Toyota. Toyota decided to end the manufacturing of the Hino Contessa. (The original plan was for Dunham and Brock to have the exclusive distributorship of the Hino Contessa and bring it to the United States.) Later, Dunham returned to Japan and raced both motorcycles and cars on Japan's Suzuka Circuit and the Fuji Speedway. Dunham's racing talents later led him to work as a stunt man, for the Japanese film industry. Because of his diverse background and his ability to speak Japanese fluently, his opportunities multiplied. This is what helped jump start Dunham's acting career. In 1980, Dunham was interviewed about his career as an actor/stunt man and race car driver for The Cape Cod Times newspaper. In the article, he had stated to the reporter: I never really took acting, too seriously. Dunham also starred in several Japanese and American commercials, for various soft drinks.

(American race car designer and race car driver Pete Brock, of Brock Racing Enterprises or BRE, is not be confused with the Australian race car driver Peter Brock. Ironically, Peter Brock died on September 8, 2006, while racing the Shelby Daytona Cobra coupe, which had been designed by American race car designer and driver, Pete Brock.)

Dunham also authored three books: Tokyo Unzipped, The Art of Being Japanese, and Alice in Blunderland, which he published under the name Bob Dunham. His books were all satirical novels, made to poke fun of the common stereotypes Americans have of the Japanese culture.

Dunham lived in Tokyo for over 22 years. His first wife was Diane Drown of Natick, Massachusetts. They were married for a year and were quickly divorced. In 1954, Dunham married a Japanese woman named Keiko. They had two children, Barbara Ann (Dunham) Subayashi and Daniel Alan Dunham. They divorced in 1968. Later, Dunham met a Japanese fashion model, named Setsuko Sazawa. They were married in February 1969. They had two children, Emiko Jade (Dunham) Frost and Marcia (Dunham) Narita. Later, Dunham and his wife Setsuko moved to Denenchofu, an affluent suburb of Tokyo, Japan, where they lived from 1973-75. In 1975, Dunham moved his family to the United States, due to the energy crisis and lack of acting work. Dunham and hs family moved to Truro, Massachusetts, an isolated area of Cape Cod. Later, he became a freelance writer, often contributing material to such magazines as Car and Driver, Road and Track, and The Saturday Evening Post.

Dunham lived all over Cape Cod, Massachusetts, between 1975-1987. He lived in Truro, Wellfleet, South Orleans, and Brewster, Massachusetts. In 1984, he divorced his third wife Setsuko and moved back to Truro, Massachusetts. In 1987, he moved to a gated community in Sarasota, Florida. He was very active in local theater productions in Sarasota. In 1998, he directed a movie called, Samantha. It was based on a short story he wrote many years ago in Japan called, The Nine Lives of Miss Hama's Cats. (The movie was completed two years later but was never sold.)

Dunham passed away alone in his home, sometime in late July 2001. His body was discovered in his home in Sarasota, on August 6, 2001, by the Sarasota Sheriff's Office. He died from a massive stroke, at the age of 70. Dunham is buried at the National Cemetery in Bourne, Massachusetts, on Cape Cod.