Interior design is a multi–faceted profession in which creative and technical solutions are applied within a structure to achieve a built interior environment.

  The interior design process follows a systematic and coordinated methodology, including research, analysis, and integration of knowledge into the creative process, whereby the needs and resources of the client are satisfied to produce an interior space that fulfills the project goals.

There are a wide range of working conditions and employment opportunities within interior design. Large and tiny corporations often hire interior designers as employees on regular working hours. Designers for smaller firms usually work on a contract or per-job basis. Self-employed designers, which make up 26% of interior designers,usually work the most hours. Interior designers often work under stress to meet deadlines, stay on budget, and meet clients' needs. In some cases, licensed professionals review the work and sign it before submitting the design for approval by clients or construction permisioning. The need for licensed review and signature varies by locality, relevant legislation, and scope of work. Their work can involve significant travel to visit different locations, however with technology development, the process of contacting clients and communicating design alternatives has become easier and requires less travel.

Interior design earnings vary based on employer, number of years with experience, and the reputation of the individual. For residential projects, self-employed interior designers usually earn a per-hour fee plus a percentage of the total cost of furniture, lighting, artwork, and other design elements. For commercial projects, they may charge per-hour fees, or a flat fee for the whole project. The median annual earning for wage and salary interior designers, in the year 2006, was $42,260. The middle 50% earned between $31,830 and $57,230. The lowest 10 percent earned less than $24,270, and the highest 10 percent earned more than $78,760. For example, if a person opens a business and decides to specialize in furniture design and flooring, they will get only clients focusing on these topics rather than a variety of every type of issue that comes with designing a home.

A style, or theme, is a consistent idea used throughout a room to create a feeling of completeness. Styles are not to be confused with design concepts, or the higher-level party, which involve a deeper understanding of the architectural context, the socio-cultural and the programmatic requirements of the client. These themes often follow period styles. Examples of this are Louis XV, Louis XVI, Victorian, Islamic, Feng Shui, International, Mid-Century Modern, Minimalist, English Georgian, Gothic, Indian Mughal, Art Deco, and many more.

The evolution of interior decoration themes has now grown to include themes not necessarily consistent with a specific period style allowing the mixing of pieces from different periods. Each element should contribute to form, function, or both and maintain a consistent standard of quality and combine to create the desired design. A designer develops a home architecture and interior design for a customer that has a style and theme that the prospective owner likes and mentally connects to. For the last 10 years, decorators, designers, and architects have been re-discovering the unique furniture that was developed post-war of the 1950s and the 1960s from new material that were developed for military applications. Some of the trendsetters include Charles and Ray Eames, Knoll and Herman Miller. Themes in home design are usually not overused, but serves as a guideline for designing.

Interior decoration (which is not to be confused with interior design, as noted above) has become the subject of television shows. In the United Kingdom(UK), popular interior decorating programs include 60 Minute Makeover (ITV), Changing Rooms (BBC) and Selling Houses (Channel 4). Famous interior designers whose work is featured in these programs include Linda Barker and Laurence Llewelyn-Bowen. In the United States, the TLC Network aired a popular program called Trading Spaces, a show based on the UK program Changing Rooms. In Canada, popular shows include Divine Design with Candice Olsen and Design Inc., featuring Sarah Richardson. In addition, both Home & Garden Television (HGTV) and the Discovery Home networks also televise many programs about interior design and decorating, featuring the works of a variety of interior designers, decorators and home improvement experts in a myriad of projects. Fictional interior decorators include the Sugarbaker sisters on Designing Women and Grace Adler on Will & Grace. There is also another show called "Home MADE". There are two teams and two houses and whoever has the designed and made the worst room, according to the judges, is eliminated. Another show on the Style Network, hosted by Niecy Nash, is Clean House where they re-do messy homes into themed rooms that the clients would like. Other shows include Design on a Dime and Designed to Sell and The Decorating Adventures of Ambrose Price. The show called "Design Star" has become more popular through the 5 seasons that have already aired. The winners of this show end up getting their own TV shows, of which are Color Splash hosted by David Bromstad, Myles of Style hosted by Kim Myles, Paint-Over! hosted by Jennifer Bertrand, The Antonio Treatment hosted by Antonio Ballatore, and finally Secrets from a Stylist hosted by Emily Henderson.

Other early interior decorators:

• Elsie de Wolfe
• Syrie Maugham
• Sybil Colefax
• Dorothy Draper
• Pierre François Léonard Fontaine

Many of the most famous designers and decorators during the 20th Century had no formal training. Sister Parish, Mark Hampton, Robert Denning and Vincent Fourcade, Stephen Chase, Mario Buatta, John Saladino, Kerry Joyce, Kelly Wearstler, Stéphane Boudin, Georges Geffroy, Emilio Terry, Carlos de Beistegui,Nina Petronzio, Lorenzo Mongiardino, Billy Baldwin, David Nightingale Hicks, Barbara Barry, Jeanine Naviaux, Michael Smith and many others were trend-setting innovators in the worlds of design and decoration.