Guardiola watched on as his side defeated Borussia Dortmund 2-0 to clinch the DFB-Pokal on Saturday, after also securing the Bundesliga title in his first season with the club.
The 43-year-old has now won 18 pieces of silverware since replacing Frank Rijkaard at Barcelona ahead of the 2008-09 season, although the Spaniard insisted it has not been easy for him in Bavaria.
"It's my fifth year as a trainer of a professional football team, my sixth year overall as a coach," said Guardiola.
"One year I was coaching the second team of Barcelona. After four years working with the first team of Barcelona, this has been the most important and challenging season of my trainer career.
"My German is not that good yet so I have to convince my players every time. After Bayern won the treble last season with Jupp Heynckes it was not easy for me."
Guardiola also paid tribute to the Bayern board for hiring him and said he wants to bring more success to the club.
"I've got my own idea of playing football," he added. "That's why Matthias Sammer, Karl-Heinz (Rummenigge) and Uli (Hoeness) signed me.
"We just changed a few things, but the mentality was still great and also the players' attitude and responses to that were excellent.
"This season was not easy for me. Obviously the Super Cup title against Chelsea (won in August) helped me a lot, it gave me time to work on my plan."
