He started his career at the Butler Daily Democrat and later worked as a photographer for the Emporia Gazette, The Kansas City Star, and Los Angeles Times newspapers.

Following his Napa Valley assignment in 1978, O'Rear developed an interest in wine photography; relocated to St. Helena, California; and formed the Los Angeles-based stock photo agency Westlight in 1980.

In January 1998, he captured a stock photo of a green rolling hill and cirrus clouds during a daytime sky in southern Sonoma County.

After the acquisition of Westlight by Bill Gates's Corbis, O'Rear was approached by Microsoft, who offered to buy full rights to the photograph; they renamed it Bliss and chose as the default wallpaper of Windows XP.

[4][5] O'Rear grew up in his home state and was interested in aircraft during his youth, obtaining a pilot license by the age of 16.

[2][6] During his elementary education, O'Rear participated in a shuffleboard competition in 1952 and authored his first newspaper article for the Bates County Democrat in 1955.

[24] He took photographs of Honolulu, Hawaii,[25] Nebraska,[26] Las Vegas,[27] Arizona, California,[28] and Hoover Dam on the Colorado River.

[29] C. Jerry Simmons of Prologue saw O'Rear's work in Nebraska as "a lasting snapshot of Midwest America".

[30] Regarding his nature photographs, O'Rear showed the destruction of the environment "as a threat to the social future of the United States," according to historian Caleb Wellum.

[6][32] During his time at Napa Valley, O'Rear established connections with winemakers Robert and Margrit Mondavi.

[11][34][35] The photograph for "The Bird Men" was taken in North Dakota; he hoped that he would capture a pelican flying to their roost but was unsuccessful.

[11] While working with National Geographic, he learned to use small strobes and taught the subject at the Santa Fe Photographic Workshop.

O'Rear co-founded Westlight, a Los Angeles-based photo agency, with photographer Craig Aurness in 1980.

[36] While on his way to visit his girlfriend, Daphne Larkin, in Marin, O'Rear made a photograph of a lush green rolling hill and cirrus clouds during a daytime sky.

[37][39] He recalled that he was looking for an opportunity to shoot a photograph that day, considering that a storm had passed over and winter rains had left the hill green.

[42][44] By the time of its acquisition, Westlight was estimated to have been one of the largest stock photo agencies in the United States.

Corbis had previously hired O'Rear to photograph wine auctions in Burgundy in 1995,[45] and after the acquisition, they digitized Westlight's images.

[40]: 3:37, 3:50 [6] O'Rear had to personally deliver the film to Microsoft in Seattle due to delivery services declining because of its high value.

[6][37] Another photograph of his, titled Red Moon Desert in Windows XP, was initially considered the default wallpaper.

[50] Because of Windows XP's success, Bliss has been speculated to be the most-viewed photograph in history by journalists and Microsoft.

[57] In September 2023, The Transylvania Times named O'Rear the "Transylvanian of the Week" in recognition of his career accomplishments.

[64] Fred Tasker of Miami Herald positively received the Chardonnay: Photographs from Around the World book.