It was published by MicroPro International and originally written for the CP/M-80 operating system (OS), with later editions added for MS-DOS and other 16-bit PC OSes.

WordStar was written with as few assumptions as possible about the operating system and machine hardware, allowing it to be easily ported across the many platforms that proliferated in the early 1980s.

As the market became dominated by the IBM PC and later Microsoft Windows, this same portable design made it difficult for the program to add new features, and affected its performance.

Seymour I. Rubinstein was an employee of early microcomputer company IMSAI, where he negotiated software contracts with Digital Research and Microsoft.

He founded MicroPro International Corporation in September 1978 and hired John Robbins Barnaby as programmer, who wrote a word processor, WordMaster, and a sorting program, SuperSort, in Intel 8080 assembly language.

After Rubinstein obtained a report that discussed the abilities of contemporary standalone word processors from IBM, Xerox, and Wang Laboratories, Barnaby enhanced WordMaster with similar features and support for the CP/M operating system.

Besides word-wrapping (still a notable feature for early microcomputer programs), this last was most noticeably implemented as on-screen pagination during the editing session.

Using the number of lines-per-page given by the user during program installation, WordStar would display a full line of dash characters onscreen showing where page breaks would occur during hardcopy printout.

By 1984, the year it held an initial public offering, MicroPro was the world's largest software company with 23% of the word processor market.

WordStar's ability to use a "non-document" mode to create text files without formatting made it popular among programmers for writing code.

This carried with it an unfortunate performance penalty as everything had to be "double" processed (meaning that the DOS API functions would handle screen or keyboard I/O first and then pass them to the BIOS).

By that point, MicroPro had dropped the generic MS-DOS support and WordStar 4.0 was exclusively for IBM compatibles, which differed from MS-DOS-compatible programs in terms of screen addressing.

Also introduced were simple macros (shorthand) and the install program was completely updated to include features like reprogramming function keys and an extensive printer support.

"[17] Besides the ready availability of third-party books explaining WordStar in detail,[6] the program's extensive and configurable onscreen help facility (help text appeared in a resizable window at the top of the screen) made it easy to use an illegal copy.

BYTE stated that WordStar 2000 had "all the charm of an elephant on motorized skates", warning in 1986 that an IBM PC AT with hard drive was highly advisable to run the software, which it described as "clumsy, overdesigned, and uninviting ...

However, its lasting legacy on the word processing industry was the introduction of three keyboard shortcuts that are still widely used, namely, Ctrl+B for boldfacing, Ctrl+I for italicizing, and Ctrl+U for underlining, text.

PC Magazine wrote in 1983 that MicroPro's "motto often seems to be: 'Ask Your Dealer'",[10] and in 1985 that[19] Almost since its birth 4 years ago, MicroPro has had a seemingly unshakable reputation for three things: arrogant indifference to user feedback ("MicroPro's classic response to questions about WordStar was, "Call your dealer"); possession of one of the more difficult-to-use word processors on the market; and possession of the most powerful word processor available.By late 1984, the company admitted, according to the magazine, that WordStar's reputation for power was fading,[19] and by early 1985, its sales had decreased for four quarters while those of Multimate and Samna increased.

In September 1983, it published WordStar clone NewWord, which offered several features the original lacked, such as a built-in spell checker and support for laser printers.

WordStar was the program of choice for conservative intellectual William F. Buckley, Jr., who used the software to write many works, including his last book.

As users became more familiar with the command sequences, the help system could be set to provide less and less assistance until finally all on-screen menus and status information would be turned off.

Commands to enable bold or italics, printing, blocking text to copy or delete, saving or retrieving files from disk, etc.

Although many of these keystroke sequences were far from self-evident, they tended to lend themselves to mnemonic devices (e.g., Ctrl-Print-Bold, Ctrl-blocK-Save), and regular users quickly learned them through muscle memory, enabling them to rapidly navigate documents by touch, rather than memorizing "Ctrl-S = cursor left."

The original WordStar interface left a large legacy, and many of its control-key command are still available (optionally or as the default) in other programs, such as the modern cross-platform word processing software TextMaker and many text editors running under MS-DOS, Linux, and other UNIX variants.

The TEXT editor built into the firmware of the TRS-80 Model 100 portable computer supported a subset of the WordStar cursor movement commands (in addition to its own).

Popular modern word processing software WordPerfect can open or save to WordStar documents, enabling users to move back and forth.

MailMerge was an add-on program (becoming integrated from WordStar 4 onwards) which facilitated the merge printing of bulk mailings, such as business letters to clients.

[46] As a product enhancement, in the late 1980s WordStar 5 came bundled with PC-Outline, a popular DOS outliner then available from Brown Bag Software, Inc. in California.

For several years Hebrew-English WordStar was the de facto WYSIWYG word processor leader until, inevitably, it was ousted by newer competitors.

Occasionally short machine-language programs had to be entered in a patch area in WordStar, to provide particular screen effects or cope with particular printers.

[56] In addition German software author Martin Vieregg has sold the Write&Set package, a shareware GUI based WordStar clone for Microsoft Windows and OS/2–eComStation since the latter half of the 1990s, and for Linux and OS X as well.