[5] The area now occupied by Sunnyvale was inhabited by various Native American tribes in the years before the European conquest of the Americas.

During this time, settlers migrated to present-day Sunnyvale, naming the hamlet they founded Long Creek.

In the year 1953, the hamlets of Hatterville, New Hope, Long Creek, and Tripp merged under the name Sunnyvale.

Since, there are many reminders of Sunnyvale's rich history, like the old New Hope School; the Tripp First Baptist Church, built in 1882; and many antique houses.

The Long Creek Cemetery in southern Sunnyvale is over 150 years old, and the first recorded burial there is that of Leona Crownover Caldwell, dated October 2, 1855.

On June 5, 2023, Sunnyvale made national headlines after story broke of a mass shooting incident.

[12] According to the United States Census Bureau, the town has a total area of 16.8 square miles (44 km2), all land.

[20] As of the same year the council members are Ryan Finch, Kevin Clark, Manu Danny, Mark Eldridge, Larry Allen, and Jonathan Freeman.

[19] In 2000 a U.S. district court ruled that Sunnyvale had enacted planning and zoning practices that were in place to exclude the development of apartments and small single family lots.

Sunnyvale's government responded, saying that it had taken appropriate steps to approve the creation of low income housing.

Sunnyvale is in Texas State House District 112, represented by Republican Angie Chen Button.