The 19-year-old former Chesterfield player has netted 28 times in 21 games for Southern League Hendon this season – form which attracted interest from a host of League clubs.
German was a trainee at Chesterfield and signed a two-year pro deal with the Spireites in 2016 when he was 17, having already made three first-team appearances.
He played under three different Chesterfield managers as the club slipped down from League One to the National League before he was released last summer. Last season he scored for Alfreton Town, Sheffield and Matlock Town during loan spells.
SEE ALSO Crawley Town - a year in pictures | Are Crawley Town set to sign Non League hotshot? | Crawley Town v Colchester United: Reds looking to make a positive start to 2019German linked up with Hendon and has been a regular scorer for them this season, including a goal in what was his final appearance for the club on Boxing Day.
Director of Football Selim Gaygusuz said: “Ricky is a player we have been watching since the start of the season. He had a difficult time at Chesterfield, has come back to London and dropped into non-league to try and rebuild his career and get back into the professional game.
“He is quick with a natural eye for goal and we’re delighted he’s decided to join us, because he was wanted by a lot of clubs. We got Ashley Nathaniel-George from Hendon and Ricky used to go to school with Ash and he has seen that Ash has had opportunities with us. If he can make the same impact as Ash then he could be a really good signing for us. He knows he will have to work hard to impress Gabriele Cioffi but the opportunity for him is there.”
German tweeted: "Absolutely delighted to have signed for @crawleytown i've strived to work hard to get back into the league & i'm thankful for the opportunity, onwards and upwards from here!"
German watched the win against Colchester United and will train with the squad for the first time on Thursday ahead of Saturday’s home encounter against Cheltenham.