Johannes Gensfleisch zur Laden zum Gutenberg

Not sure if it was the first, but certainly pioneering in terms of randomisation, Beowolf. I also love the anecdotal note about spelling.

Both Erik van Blokland and Just van Rossum have made a number of pioneering contributions to type engineering, production and design, including Superpolator, TTX and Robofab. They also maintain a wonderfully lo-fi website.

Technicians are great, but to me Evert Bloemsma's Legato stands out as the most significant cultural contribution to type design.

hhp

Arnold Pannartz and Konrad Sweinheim, who introduced typography to Italy.
Mainz, the birthplace of printing, where they worked, had become a war zone in 1462, causing a diaspora of printers. Three years later they published the first printed book in Italy. Who knows what hardships they faced during those three years?
Quite apart from getting their gear across the Alps (or rebuilding it from scratch), they had to change the look of type to suit their new clientelle.
While Gutenberg had been a technical pioneer, he mimicked the scribes.
Sweynheim & Pannartz made the first humanist/Roman typefaces, not just copying the local writing style in Italy, but creating a new hybrid form for the new medium that, refined by Jenson shortly afterwards, became the model we use to this day.
Here are S&P’s types of 1465 and 1467, showing the change they made.

No one took more gorgeously played out risks than Novarese.
No one spoke with more authenticity than Morris Fuller Benton.
No one had a bigger hand in the feel of today's world than Excoffon
Hubert Jocham's sans' will be like what Shakespeare was to English,
or perhaps more aptly, what Martin Luther was to German.