Ernie Banks, shown in 2007, finished his career with 512 home runs and is in the Hall of Fame. Moreover, the enthusiasm of his “Let’s play two” mantra provided a great life lesson. (Chris Mcgrath/Getty Images)

When we are sifting for childhood heroes, we look for what we lack. Even though I grew up in the District, I looked all the way to Chicago to find Ernie Banks. Then I didn’t let him go.

The late-1950s were full of major sports heroes. I could have found something that appealed deeply to me in Johnny Unitas, Arnold Palmer or Willie Mays. I certainly read enough profiles of all of them and other stars in every sports magazine. There were local D.C. heroes, like home run champion Roy Sievers, whom I fell for hard as a kid. But with all the rest of sports to choose from, I picked Banks and followed his last 15 seasons avidly.

By 1969, after I graduated from college, Ernie was the last childhood hero I still rooted for every day. In September, as his Cubs battled America’s darling, the Miracle Mets, I clung to Banks, then 38, as he staggered toward his only chance to play in a World Series. When the Cubs failed, I took a lesson from their fall, supplied by Banks, that has never left me.

If you want a defining trait, one that survives defeat, attracts affection from others and mysteriously restores itself, then it’s hard to beat enthusiasm.

“It’s a great day for a ballgame. Let’s play two” isn’t just a quotation that will probably end up in Bartlett’s. It’s philosophy.

Believe me, as someone who has covered baseball for nearly 40 years at The Washington Post, nobody wants to play 324 games, not even Ernie. “Let’s play two” is a worldview and a deep one, not a quip.

The outward joy Banks professed, even if it was partly innate to his temperament, was also a daily act of will: a lifelong private commitment to enthusiasm as a guiding principle.

For countless people, including me, it’s hard to find anybody among family or friends who’s a living example of that combination of attitude and energy. When you find a Banks, who sticks to those guns all his life, that’s the definition of a role model.

“He who would be calm must first put on the appearance of calm,” Shakespeare wrote. In other words, our emotions do not simply come from inside us and express themselves outwardly. The process can work in reverse. By putting on the outward appearance of calm — or confidence or enthusiasm or whatever quality we value — we can increase our tendency to feel that way.

Every day for 19 seasons, Banks put on that appearance of joy, convinced himself and probably some teammates that they were “playing” ball, not so much competing as publicly scrutinized pros.

So how did that sensibility stand up to The Collapse — the epitome of the sport as pain, not play?

When the Cubs crashed in September, losing 11 of 12 to go from five games ahead to 4 1/2 behind, it all happened so fast that it seemed more grotesque than dramatic and, by the end, darkly comic. Banks slumped, too. But after seven straight losses, he made a personal stand. Against the Phillies he drove in a run in the first inning, then homered in the eighth to give the Cubs a 2-1 lead; they blew it, of course. The next day, in the only Cubs win of the whole smashup, Banks drove in four of their five runs. That was the old man’s statement — not nearly enough but something.

On the final day of the season, when manager Leo Durocher, the grouch who said “Nice guys finish last,” was disengaged from his team and stuck with the disgrace of his defeat, Banks was still showing up — just to play baseball. On the season’s last day, Banks, the oldest man in the lineup, played his 155th game of the year and had a triple, homer and drove in three runs to finish the season with 106 RBI, a total he hadn’t topped since his 20s.

You need all kinds of role models as you grow up. That 1969 Cubs’ choke sealed it for me — Banks would remain one of mine. No team could fail worse. Mostly, Banks stunk, too. But I didn’t respect him any less. And nobody else seemed to either.

By 1977, Ernie had been voted into the Hall of Fame. Durocher got in by the backdoor of the Old Timers Committee in 1994 — three years after he died. Banks has been going to Cooperstown every August for a third of a century, enjoying the chatter with his fellow immortals. Leo never got to sit on the veranda of the Otesaga Hotel overlooking Lake Glimmerglass and preen. Let’s play two or nice guys finish last? Excuse me, but I call it a parable.

In a baseball sense, Banks is an immortal because he averaged 41 homers and 115 RBI a year as a shortstop from 1955 to 1960, making himself the equal of Willie Mays, Mickey Mantle or anybody else in the game for those half-dozen years.

There had never before been a middle infielder with such power. And to this day, there still hasn’t. Banks won a gold glove, too. Switching to first base and remaining a solid hitter until he had amassed 512 homers assured him a place in the Hall.

But it is the Other Banks, the man who exemplified an entire stance toward how we approach life, who will be remembered long after most of baseball’s 500-home run men are forgotten.

Perhaps fans of the 1950s, when Banks emerged, were particularly susceptible to what he embodied. From 1929 through the early 1950s, the whole country — and especially the Greatest Generation — endured a unique sequence of traumas from the Depression to World War II to McCarthyism.

The virtues that were required to survive those times were admirable but perhaps tended toward a narrow spectrum. My friends and I seemed to come from families who had all walked 20 miles to school, uphill both ways. My grandfather, a small town farmer who almost went broke in the 1930s, worked dawn to dusk. I saw him grab a snake out of a ditch, crack it like a whip and throw it back dead. My father, an Army sergeant, was in the Normandy invasion but never talked about it. Another relative, who started a union, was accused of being un-American and blackballed.

These days, it almost seems quaint to make a list of taken-for-granted American traits back then: determination, the need for rigorous education, delayed gratification and even stoicism. But Banks added something different and exciting for many of us.

Arriving in the big leagues just seven years after Jackie Robinson broke the color line, no sensible fan thought Banks had come up easy. He had even played in the Negro Leagues.

Everyone assumed that, even if Banks’s temperament tended toward cheerfulness, there was something else at work. Ernie made himself want to “play two,” even on days when he undoubtedly didn’t. And yet that habit of enthusiasm, that determination to focus on the love of the game for its own sake, seemed to become a reinforcing principle for him. The more he repeated it, lived it, the more it became true.

In short, maybe you could make yourself be happy.

All Banks’s fans will have their own affectionate version of Ernie. I imagine Banks on a hot August afternoon in Wrigley Field when the ivy vines are drooping and the Cubs flag in center field is near the bottom of the pole. He says, for the millionth time, “It’s a beautiful day for a ballgame. Let’s play two.”

A few eyes roll. But the hint has been dropped, the seed planted once more, that the focus of the day actually is baseball, the game they love. “Ernie must be nuts,” the Cubs think. “But, hell, I guess I would like to play one.”

So they do.

For more by Thomas Boswell, see washingtonpost.com/boswell.

This article previously appeared as the foreword to “Ernie Banks: Mr. Cub and the Summer of ’69” by Phil Rogers (Triumph Books, 2011)