It’s too easy to say that he lived long and prospered, although many writers will begin their remembrances of Leonard Nimoy with his time-honored catchphrase.

Nimoy—who was a writer, poet, photographer and musician as well as an actor—prospered in a singular and unique way. He was the breakout star playing the breakout character in a short-lived science fiction TV series 50 years ago. His work in that series (and in subsequent endeavors) touched and changed the lives of generations of fans in ways that few actors have ever known.

It’s not an overstatement to say that Star Trek’s Mr. Spock was one of the great folk heroes of the 20th century, and the half-human, half-Vulcan Starfleet officer will continue to influence viewers long after Nimoy’s passing. He was an inspiration to countless scientists, who, as children watching Star Trek, decided that science can be cool. He encouraged a generation of astronauts to explore the reaches of space.

But it was Nimoy’s performance as the loner, the tortured, coldly logical alien struggling with emotions that he constantly fought to keep in check, which made so many fans identify with the character. And Nimoy’s fascination with and ultimate lifelong exploration of the human condition allowed him to imbue Spock with a humanity that made the character real and deeply meaningful to a legion of fans.

Born in Boston, Massachusetts to parents who were Ukrainian immigrants and Orthodox Jews, Nimoy appeared in episodes of shows including Perry Mason, Wagon Train and Rawhide before landing the role that would define his lifetime. Initially, Nimoy struggled with the celebrity that Star Trek brought him; in 1977, he published an autobiography titled I Am Not Spock. (He would come to regret the choice of that title, publishing a second book, I Am Spock, in 1995.)

After the series ended, Nimoy continued to work, appearing in TV’s Mission: Impossible and films such as 1978’s Invasion of the Body Snatchers. But his artistic passion reached out in other directions as well. He took to the stage, starring as Vincent van Gogh in a critically acclaimed one-man performance of Vincent. He recorded campy versions of songs such as “If I Had a Hammer,”  “Put a Little Love in Your Heart” and “I Walk the Line,” along with songs that bordered on (if not crossed into) the silly, including the cult classic “Ballad of Bilbo Baggins.” He directed films, two in the Star Trek franchise, and then the wildly successful 1987 comedy Three Men and a Baby, starring Tom Sellick and Ted Danson. He wrote pages of poetry and became an accomplished photographer.

He also embarked on an exploration of his Jewish heritage. He starred opposite Ingrid Bergman in the television movie A Woman Called Golda, a film about Israeli Prime Minister Golda Meir. He produced and starred in Never Forget, the true story of a Holocaust survivor who successfully sued a group of Holocaust deniers, creating for the first time a legal finding that the Holocaust indeed happened. And his 2002 book Shekhina raised some controversy due to what some considered its risqué photography that accompanied Nimoy’s commentary on Jewish scripture and tradition.

Through it all, though, he returned to Starfleet again and again, playing Spock in two memorable episodes of Star Trek: The Next Generation as well as eight Star Trek films, including the 2009 franchise reboot and its sequel. In 2012, on the hit series The Big Bang Theory, Nimoy was the voice of a Mr. Spock doll, who assured Sheldon Cooper that playing with a toy is logical.

“Spock is definitely one of my best friends,” Nimoy would write about the character he so indelibly created. “When I put on those ears, it’s not just another day. When I become Spock, that day becomes something special.”

Later in life, Nimoy embraced social media, ending his tweets with “LLAP” (Live Long and Prosper). It was through Twitter that he told his fans last year that he had contracted chronic obstructive pulmonary disease. “I quit smoking 30 years ago,” he tweeted. “Not soon enough. I have COPD. Grandpa says, quit now!!” He continued to spend much of the last year of his life urging his followers to give up smoking.

Upon the news of his death, social media exploded as a multitude of fans expressed their condolences. While many relied on “Live long and prosper” to articulate their sentiments, others relied on another famous Spock quote to convey how they felt about the man and the artist who had touched their lives so profoundly.

“I have been,” they told Leonard Nimoy, “and always shall be, your friend.”