Henderson helped his teams reach the World Series four times during his career (1986 with Boston, 1988-1990 with Oakland), though his only ring came in 1989 when the A's defeated their Bay Area rival San Francisco Giants in four games.

The outfielder is probably best remembered for his two-out, two-strikes home run in the top of the ninth inning of Game 5 of the 1986 American League Championship Series. With California playing at home and in command of the best-of-seven league championship series, the Angels were on the verge of their first World Series appearance. In Game 5, the Halos held a 5-2 lead going into the ninth inning, but Boston was able to plate two runners on a hit by Wade Boggs and a home run by Don Baylor, closing the gap to 5-4.

When Henderson stepped to the plate, there were two outs and a runner on first base, Rich Gedman. On a 2-2 count with the Red Sox down to their final strike in the series, Henderson, who had entered the game as a replacement for an injured Tony Armas, hit a drive off pitcher Donnie Moore that would keep the Sox alive.

"The pitch . . . To left field, and deep, and (Brian) Downing goes back. And it's gone! Unbelievable! You're looking at one for the ages here. Astonishing! Anaheim Stadium was one strike away from turning into Fantasyland! And now the Red Sox lead 6-5! The Red Sox get four runs in the ninth on a pair of two-run homers by Don Baylor and Dave Henderson." -- Al Michaels, ABC-TV. "Hendu" began to jump for joy, even running backwards for a few steps, while making his way down the first baseline as he watched the ball sail over the outfield fence, having just smacked possibly the most stunning clutch homer since Bobby Thomson in 1951. The Angels were able to tie the score up at 6-6 in the bottom of the 9th, but in the 11th inning, Henderson hit a sacrifice fly that would go on to be the game winner.

Still down 3 games to 2, the Red Sox returned home to Fenway Park for the final two ALCS games, where they defeated the devastated Angels 10-4 and 8-1 to win the series. In a twist of fate, the Red Sox, who went on to take a 3 games to 2 lead over the New York Mets in the 1986 World Series, were one strike away from winning their first title since 1918, thanks in part to a go-ahead solo home run from Henderson. However, they couldn't finish it off, and this time they were the victim of a late-inning comeback as the Mets scored three in the bottom half of the winning to win Game 6 of the 1986 World Series, 6-5, in 10-innings at Shea Stadium. The stunned Red Sox then blew a 3-0 lead in Game 7 and ending up losing 8-5 on the road, handing the Mets the championship.

Henderson was one of baseball's biggest surprises after signing as a free agent with Oakland following a brief stint with the Giants. In the 1988 season he set career highs in batting average (.304), runs (100), hits (154), slugging average (.525) and doubles (38). He also hit 24 HRs that season and the Athletics were 23-1 when he homered.

Selected for the 1991 All-Star Game, Henderson was on his way to the best season of his career batting in the number-two spot in the A's lineup behind Rickey Henderson. The slugger was consistenly getting fastballs to hit because the speedy Rickey was a stolen base threat every time he reached safely. "Hendu" was batting .340 before the All-Star break, but his average dipped in the second-half of the season and he finished the year at .276, though he did hit a career-high 25 HRs. That year, Henderson blasted 3 homeruns in consecutive at-bats against Minnesota.

While he did come back to hit 20 HRs in 1993, Henderson was never the same player after blowing out his knee in the previous season. He finished up his career as a backup with the Kansas City Royals in 1994.

In 14-seasons Henderson batted .258 with 197 homeruns, 708 RBI, 710 runs, 286 doubles, and 50 stolen bases in 1538 games. In eight post-season series (four ALCS and World Series appearances a piece), he hit .298 with 7 HRs, 20 RBI, 24 runs and a .570 SA.

Today, Henderson works as a broadcaster for the Seattle Mariners.