The appointment of Lewis as McLoughlin's replacement and minister without portfolio was initially overshadowed by the mistaken announcement that Grayling was being moved from Transport secretary to Conservative chairman.
After a hard start when her party had to delete a tweet naming the wrong person as its new chairman, May went on to promote more women, black and younger lawmakers to challenge critics who call the Conservatives "male, pale and stale".
May's most senior colleagues, including Chancellor Philip Hammond, Foreign Secretary Boris Johnson, Brexit Secretary David Davis and Home Secretary Amber Rudd were all understood to be remaining in post.
BBC political editor Laura Kuenssberg had also named Grayling, citing two unnamed sources, but later tweeted that another source said immigration minister Brandon Lewis would be the new chairman.
While viewed as a chance at a fresh start, the reshuffle brings risks of upsetting the delicate balance of eurosceptic and pro-European ministers.
His replacement was announced on Twitter, only for the tweet to be nearly immediately deleted. The pair will be charged with modernising the Tories, rejuvenating the membership and improving the party's campaigning techniques, including using social media better.
Sir Patrick was widely tipped to pay the price for the party's failure at last year's snap general election when the Tories saw their Commons majority wiped out.
The reshuffle was sparked in part by the resignation of May's ally, Damian Green as the de-facto deputy prime minister, after police who were investigating a separate matter revealed they had found thousands of pornographic images on his computer.
He was also blamed for the disastrous party conference, where magnetic letters fell off during May's speech which was being televised live.
In a major shake-up of CCHQ, the Conservatives announced prominent backbencher James Cleverly as deputy chairman, junior minister Chris Skidmore as vice chairman for policy, Maria Caulfield as vice chair for women, and 2017 intake MPs Kemi Badenoch and Ben Bradley as vice chair for candidates and vice chair for youth respectively.
Changes to the junior ministry will take place on Tuesday, London time.