He played in Major League Baseball (MLB) for the Seattle Mariners, Boston Red Sox, San Francisco Giants, Oakland Athletics, and Kansas City Royals during his 14-year career, primarily as an outfielder.

Henderson is best remembered for the two-out, two-strike home run he hit in the top of the ninth inning in Game 5 of the 1986 American League Championship Series.

[1] Henderson was born in Merced, California and grew up in nearby Dos Palos, where he attended high school and played both baseball and football.

[2] Henderson's uniform numbers—42 in football, 22 in baseball—were both retired by the Dos Palos Broncos, which inducted him into the school's Hall of Fame in 2012 and named their baseball field in his honor.

[3] His first MLB hit came several games into the season—a home run against Oakland pitcher Steve McCatty,[4] after Henderson had been hitless in his first nine major league plate appearances.

[5] From when he was recalled until the end of the season, he appeared mostly as a late-innings defensive replacement, finishing his first MLB year with a .167 average in 59 games played, with 6 home runs at 13 RBIs.

Most of his appearances were as a late-game defensive replacement in center field, or as a pinch hitter – he had only 51 at bats, collecting 10 hits (.196 average) with one home run and three RBIs.

The Angels had a 5–2 lead going into the ninth inning and were three outs away from their first-ever trip to the World Series, but the Red Sox closed the gap to 5–4 on a two-run home run by Don Baylor.

When Henderson stepped to the plate to face reliever Donnie Moore, there were two outs and catcher Rich Gedman was on first after being hit by a pitch.

Then, on Moore's seventh pitch of the at bat, Henderson hit a drive to left that cleared the outfield wall, stunning the Angels and all of Anaheim Stadium.

[17] Henderson was Boston's starting center fielder for the first month of the 1987 season, and during April he hit .239 (17-for-71, also 18 strikeouts) with 3 home runs and six RBIs.

After having only six at bats in July, he received more playing time in August and raised his season totals to a .234 average with 8 home runs and 25 RBIs, but on September 1 the Red Sox traded him to the San Francisco Giants for a player to be named later (ultimately, Randy Kutcher).

His performance proved to be one of the season's biggest surprises[19] as he set career highs in batting average (.304), runs (100), hits (154), doubles (38), RBIs (94), and slugging percentage (.525).

[19] Henderson received consideration during AL MVP voting and finished 13th, with the award going to his Athletics teammate Jose Canseco.

The 1990 season again found Oakland winning the AL West, this year with a 103–59 record, finishing ahead of the Chicago White Sox by 9 games.

[18] Oakland met the AL East winning Red Sox in the 1990 ALCS and swept them in four games, as they had done two years prior.

During the first half of the 1991 season, Henderson hit well, batting .298 with 18 home runs and 50 RBIs, and was selected for the 1991 All-Star Game with over 1.5 million fan votes.

[20] He started the All-Star Game for the AL in right field, and was 0-for-2 at the plate before being pinch hit for by Rubén Sierra in the sixth inning.

[21] In August, Henderson hit three home runs in a single game, in a losing effort against the Minnesota Twins, with all three coming in consecutive at bats off starting pitcher David West.

While Oakland won the AL West (then lost to Toronto in six games in the 1992 ALCS), Henderson was left off the postseason roster due to his injury.

Before the start of the 1994 season, Henderson was signed as a free agent by the Kansas City Royals, as the club intended to platoon him with Bob Hamelin.

Shortly after his 36th birthday, Henderson retired on July 29, 1994,[25] which was his last MLB appearance – against the Minnesota Twins, he played the final two innings of the game as a defensive replacement in left field.

[28] After retiring as a player, Henderson lived in the Seattle area[27] and remained involved in baseball as an agent, broadcaster, and running fantasy camps.

He returned to the Mariners' radio booth during 2011 and 2012 as one of a rotating crew of part-time announcers working with Rick Rizzs who succeeded the deceased Dave Niehaus.

[30][31] Henderson suffered a heart attack and died at Harborview Medical Center in Seattle on December 27, 2015,[32][33] approximately two months after having undergone a kidney transplant.