Germany beat Spain to win under-21 Euro
It is Germany's second title in the age group following their triumph in 2009, while Spain failed to expand their collection of four titles.
Hertha Berlin winger Weiser sent a header arcing over Spanish keeper Kepa Arrizabalaga and into the far corner on 40 minutes for his first goal of the tournament following a cross from right-back Jeremy Toljan.
"The goal made everything very difficult," said Spanish coach Albert Celades, a former defensive midfielder with Real Madrid and Barcelona.
"The first half was key for us, we tried to do everything in the second half but time was running out for us.
"Of course we're sad, this was the final (but) Germany is a fabulous team... playing very good football."
Spain came into the final having claimed four wins in as many games at the tournament and Celades went with the same team that started in the 3-1 semi-final victory over Italy.
Opposing coach Stefan Kuntz lost his leading striker Davie Selke to injury but welcomed back defender Niklas Stark, who had missed the semi-final drama against England when Germany won on penalties.
Spain started in high spirits, but Germany soon regained their composure to outplay their rivals in the first half, with their defence close to the half-way line and forwards never missing an opportunity to attack.
Max Meyer headed against the post early on and Germany deserved the breakthrough when it arrived with the interval approaching, with Jesus Vallejo not getting close enough to Weiser as he met Toljan's cross.
"We trusted that in the final all players can bring again close to 100 percent of their performance and that was right," said Kuntz.
"We had to bring our best technical game today with a lot of courage.
"We had a plan and they did it really, really good. It's not easy to play against our team when they haveÂ so much courage."
Spain came out of the changing room more determined to attack in the second half, but the closest they came to equalising was a left-footed curler from Saul Niguez that was saved by Julian Pollersbeck.
At the other end, Meyer put through Serge Gnabry who failed to beat Arrizabalaga with a low shot.
Dani Ceballos then blasted a shot just past the post while Gerard Deulofeu's shot was cleared by the German defence which easily survived the inefficient Spanish pressure of the final minutes.
With the exception of 2015 when Sweden lifted the trophy in the Czech Republic, Germany and Spain have dominated the competition since 2009 with Spain earning the honours in 2011 and 2013.