Both promising youngsters took the first step in their U.S. national team careers with solid showings against the European power.
Brooks, 20, started the game at center back and went the entire match. The Hertha Berlin man showed promising defensive ability, winning several balls on the ground and in the air. He was beaten by Edin Dzeko for a header on Bosnia's third goal, however.
AZ striker Johannsson was introduced as a 63rd-minute sub and made an immediate impact, showcasing a dynamic first touch while carving out a number of chances for himself and teammates.
The 22-year-old Alabama-born striker completed his one-time switch from Iceland to the United States just the day before the match, meaning his international future is cast with the USA, even though the Bosnia match was a non-binding friendly.
"It was very exciting," Johannsson told reporters of his debut. "I was anxious the whole game to come in to show what I can do, and I came in and I think I had a good influence on the game.
"Maybe I should have scored a goal, but hopefully that comes next game."
Brooks, meanwhile, still has the option of playing for his native Germany, though his refusal of a call-up to the Germany U-21 side and acceptance of a USA call-up bodes well for the Yanks' chances of permanently retaining the highly promising center back.
"It's a nice experience," an enthusiastic Brooks said after the game. "I bring stuff from here to my club, it's a nice experience to play for a national team."
Both players could be permanently cap-tied to the United States with an appearance in either of the team's next two World Cup qualifiers: at Costa Rica on Sept. 6 and at home against Mexico on Sept. 10.