Harvey's 46th save preserved Langston's 19th victory, 3-1, over the Kansas City Royals Sunday before 27,588 at Anaheim Stadium.
"It's very unfortunate where we finished up," Langston said of the Angels' 81-81 record. "I still think this is a very good team."
Langston (19-8) struck out a season-high 10 and got the most victories by an Angel pitcher since Nolan Ryan won 19 in 1977.
"We're a better team than where we are in the standings," added Langston, who was 10-17 last season. "In the second half, we just didn't play well and did not do the things we're capable of doing."
Harvey's save was the club-record 50th for the bullpen, one more than the mark set in 1970.
"If we'd finished first, it would be different," Harvey said. "We go home today and I'd trade it all in to be playing Tuesday."