George Millay, the US theme park entrepreneur who has been credited with creating two major genres of theme parks has died at the age of 76.

Following an early career as a restaurateur, Millay opened the first SeaWorld in San Diego, US, in 1964. Two years later, he successfully introduced the first killer whale to live in captivity at the park.

Under Millay’s direction, SeaWorld expanded with new sites in Ohio (1970) and Orlando (1973).

While directing the SeaWorld operations, Millay was also part of the team which opened the Magic Mountain theme park – currently owned by Six Flags – in Valencia, California, US, in 1971.

After a controversial dispute with the SeaWorld board of directors in 1974, Millay resigned and spent the next three years developing the Wet ‘n Wild waterpark concept.

The first Wet ‘n Wild site opened in Orlando, Florida in 1977 and Millay went on to open six others before selling the parks in 1998.

He was inducted into the International Association of Amusement Parks & Attractions’ (IAAPA) Hall of Fame in 1994 and also received the World Waterpark Association’s lifetime Achievement Award in 2004.

Jan Schultz, a former SeaWorld executive, said: “George was a creative, brilliant guy and in my mind will always be among the top five list of the most brilliant, creative minds alongside the likes of Walt Disney and Henry Ford.”

Millay is survived by his wife, four children and seven grandchildren.