Двойное отрицание на английском...

здесь ВООБЩЕ нет двойного отрицания в смысле грамматики) ) He did't pretend to be a footballer neither he played for the team (или вместо neither, по-русски, word-by-word translation)) можно перевести -and he didn't play for the team)

два раза.

He neither pretended to be a footballer nor did he play for the team.

При однородных сказуемых английский язык имеет тенденцию "экономить" на вспомогательных глаголах. Так что два раза didn't не нужно.
Ещё варианты перевода:
He did not pretend to be a footballer or play for the team;
He did not pretend to be a football player, nor did he play for the team.
А собственно двойное отрицание -- это, к примеру,
It was not impossible;
She was not at all unable to do that.

В этом случае можно и два раза употребить потому что отрицаются два Разных глагола.
Под двойным отрицанием обычно понимаются выражения вроде таких:
He doesn't play no football.
I ain't never done that.
I have not got no time.
и т. п.
Подробней сам погугли.

Discussing English grammar, the term "double negative" is often[2] though not universally[3][4] applied to the non-standard use of a second negative as an intensifier to a negation.

Although they are uncommon in written English, double negatives are employed as a normal part of the grammar of Southern American English, African American Vernacular English, and most British regional dialects, particularly the East London and East Anglian dialects. Dialects which use double negatives do so consistently and follow a different set of descriptive linguistic rules