Gill was commissioned to develop his alphabet into a full metal type family by his friend Stanley Morison, an influential Monotype executive and historian of printing.

Morison hoped that it could be Monotype's competitor to a wave of German sans-serif families in a new "geometric" style, which included Erbar, Futura and Kabel, all being launched to considerable attention in Germany during the late 1920s.

The "O" is an almost perfect circle and the capital "M" is based on the proportions of a square with the middle strokes meeting at the centre; this was not inspired by Roman carving but is very similar to Johnston.

Following the traditional serif model the italic has different letterforms from the roman, where many sans-serifs simply slant the letters in what is called an oblique style.

This is clearest in the "a", which becomes a "single storey" design similar to handwriting, and the lower-case "p", which has a calligraphic tail on the left reminiscent of italics such as those cut by William Caslon in the eighteenth century.

[21][28][f] Gill had greatly admired Johnston's work on their Underground project, which he later wrote had "redeemed the whole business of sans-serif from its nineteenth-century corruption" of extreme boldness.

[36]) Morison also intervened to insist that the letters "J" and "Q" be allowed to elegantly descend below the baseline, something not normal for titling typefaces which were often made to fill up the entire area of the metal type.

[8][45] In the regular or roman style of Gill Sans, some letters were simplified from Johnston, with diamond dots becoming round (rectangles in the later light weight) and the lower-case "L" becoming a simple line, but the "a" became more complex with a curving tail in most versions and sizes.

[8][31] The "R" with its widely splayed leg is Gill's preferred design, unlike that of Johnston; historian James Mosley has suggested that this may be inspired by an Italian Renaissance carving in the Victoria and Albert Museum in London.

The titling capitals of Gill Sans were first unveiled at a printing conference in 1928; it was also shown in a specimen issued in the Fleuron magazine edited by Morison.

[13][37] While initial response was partly appreciative, it was still considered dubious by some ultra-conservative printers who saw all sans-serif type as modern and unsound; one called it "typographical Bolshevism".

The characters were drawn mirrored on paper in large plan diagrams by the experienced drawing office team, led and trained by Pierpont and Fritz Steltzer, both of whom Monotype had recruited from the German printing industry.

Its success was aided by Monotype's sophisticated marketing, led by Gill's supporter Beatrice Warde, and due to its practicality and availability for machine composition in a very wide range of sizes and weights.

[57] William Addison Dwiggins described it and Futura as "fine in the capitals and bum in the lower-case" while proposing to create a more individualistic competitor, Metro, for Linotype around 1929.

[58] Modern writers, including Stephen Coles and Ben Archer, have criticised it for failing to improve on Johnston and for unevenness of colour, especially in the bolder weights (discussed below).

[73][74] Harling reviewed it as "dismal" and sarcastically commented that "typographical historians of 2000AD (which isn't, after all, so very far away) will find this odd outburst in Mr Gill's career, and will spend much time in attempting to track down this sad psychological state of his during 1936.

[59][28]) Gill argued in his Essay on Typography that the nineteenth-century tendency to make sans-serif typefaces attention-grabbingly bold was self-defeating, since the result was compromised legibility.

[18][82][83][84][85] In particular, in the standard designs for Gill Sans the numeral "1", upper-case "i" and lower-case "L" are all a simple vertical line, so an alternative "1" with a serif was sold for number-heavy situations where this could otherwise cause confusion, such as on price-lists.

[18][21] With the increasing popularity of Futura Gill Sans was not alone in being adapted: both Erbar and Dwiggins' Metro would undergo what historian Paul Shaw has called a "Futura-ectomy" to conform to taste.

[5] According to Rhatigan and other sources, by the end of the metal type period Gill Sans had been released in the following styles (not all sold at the same time): Titling series were capitals-only.

[16][95] Infant designs of fonts are often used in education and toys as the letters are thought to be more recognisable to children being based on handwriting, and are often produced to supplement popular families such as Gill Sans, Akzidenz-Grotesk and Bembo.

[107] Gill Sans Nova adds many additional variants, including some of the previously undigitised inline versions, stylistic alternates and an ultra-light weight which had been drawn for Grazia.

[116] Peter Wiegel digitized a modified variant of Gill Sans Bold Condensed that used on road signs in former East Germany until 1990 named TGL 12096-1 typeface.

[123] Paul Shaw, a historian of printing, has described it as a key element of the 'Modernist classical' style from the 1930s to the 1950s, that promoted clean, spare design, often with all-capitals and centred setting of headings.

Mosley has commented that in 1960 "orders unexpectedly revived" for the old Monotype Grotesque design: "[it] represents, even more evocatively than Univers, the fresh revolutionary breeze that began to blow through typography in the early sixties.

[133][134][135][136] Of the period from the 1930s to 1950s, when he was growing up, James Mosley would later write: The Monotype classics dominated the typographical landscape ... in Britain, at any rate, they were so ubiquitous that, while their excellent quality was undeniable, it was possible to be bored by them and to begin to rebel against the bland good taste that they represented.

"[151] The Sheffield type foundry Stephenson Blake rapidly released a commercial competitor named Granby, influenced by Gill Sans, Johnston and Futura.

[166][167] The category of humanist sans-serif typefaces, which Gill Sans helped to define, saw great attention during the 1980s and 1990s, especially as a reaction against the overwhelming popularity of Helvetica and Univers in the 1960s and 1970s.

[18][192][193][194] That makes it legally permissible to create alternative digitised versions of Gill Sans although not necessarily of later Monotype additions to the font such as the book weight and euro sign.

[198][199] A direct clone of the medium weight, Sans Guilt, was released by Brussels open source design group OSP in 2011, but it contains several obvious glitches such as misaligned "w" and "x" characters.