Kathy finished San Marcos High School in Santa Barbara, California. Anthony Edwards, Cady Huffman, Linus Huffman and Eric Stoltz also studied there.

She had a huge success in the modeling business. Kathy tried her in modeling in the school by Elite Model Management in 1979 at the age of sixteen. She appeared on covers for a few fashion and famous magazines as Vogue, Cosmopolitan, Forbes, Mademoiselle, Sports Illustrated Swimsuit (in 1989, 1992, 1994). Ireland was on cover of Anniversary Swimsuit Edition for the first time on its 25th, which became SI’s best selling swimsuit issue to date. Being pregnant she also appeared on the cover of the magazine. Kathy Ireland won Award "The Greatest Sports Illustrated Swimsuit Cover Of All Time" for her Ireland's 1989 cover.

Kathy said that when she was a teenager one photographer wanted her to pose topless. She did not like it. The photographer even forced her to do that, but she gave him a rebuff.

As an actress Kathy Ireland played roles in Loaded Weapon 1 (1993), Alien from L.A. (1988), Melrose Place (1994), Once Upon A Christmas (2000, 2001), Boy Meets World (1994) and other movies.

In 1994 Kathy recorded a fitness video: "Kathy Ireland's Total Fitness Workout" and she is also a contributing editor for FITNESS magazine.

In 1993 Kathy Ireland decided to create her own line of clothes. The first things Kathy designed and manufactured was a line of socks. In a very short time the company sold 100,000,000th pair of socks.

Then she designed and put on production her own clothing line of swimwear, active wear, accessories, sweaters and others. In a May 2012 Kathy Ireland was considered to be the world's richest model.

Later Ireland's billionaire friend and Berkshire Hathaway's Warren Buffett advised her to create furnish things for home. Buffett said that fashion and apparel was consistently changing, but in home it was more consistent. So Kathy has designed goods in many classifications such as the Home, Fashion Apparel, Wedding, Fine Jewelry, Baby, Children's Toys and books, Publishing, Rugs, Furniture, Pet Care, Crafts and Gift markets.

She is married with physician Greg Olsen since 1988. They have three children; Erik, Lily and Chloe. Her mother set her up with her husband.

Through entrepreneurship, in 2015 Kathy Ireland had her net worth about $420 million. In 2012 the profit from sailing goods of her company's brand amounted was about $2 billion.

She has been actively involved in campaigns connected with global women's rights and justice, education, emergency response and training for children, disease research and management, and HIV/AIDS.