For much of his career, Julian Rachlin has been known primarily as a world-class violinist and occasional violist, following in the model of one his mentors, Pinchas Zukerman.

Like Zukerman, the Lithuanian-born Rachlin has steadily increased his conducting assignments, and now about 60 percent of his time is devoted to that pursuit. Indeed, he will make his debut in that role with the Chicago Symphony Orchestra during concerts Oct. 17-20, while serving as violin soloist, something something he has done on two previous occasions with the orchestra since 1992.

“When you are just coming as a soloist, you naturally have one rehearsal and one dress [rehearsal],” Rachlin said. “But when you conduct, you have [more time] with the musicians and longer hours. That makes a big difference, because you get to know the orchestra so much better than if you’re just a guest soloist.”

Rachlin, 44, holds the position of principal guest conductor with three orchestras: the Royal Northern Sinfonia in England, Kristiansand Symphony Orchestra in Norway and Tirku Philharmonic Orchestra in Finland. As a guest conductor, he has toured Europe with the English Chamber Orchestra and led such ensembles as the Royal Liverpool Philharmonic Orchestra, Moscow Philharmonic and Vienna Symphony.

Julian Rachlin credits Mariss Jansons (above) with encouraging him to pursue conducting.

His move into conducting began when chamber orchestras like the Academy of St Martin in the Fields asked him to serve as leader for performances in which he was serving as soloist. “I wasn’t really ready for it,” he said. “I would just come and do my concerto. But then they would ask me if I wanted to work with the orchestra. They said, ‘Please share your ideas.’ And I was kind of like, ‘Really, you want my ideas?’ Because as a soloist, nobody wants your ideas. That’s the way it works. You can’t have too many cooks [in the kitchen].”

He was surprised and intrigued by these proposals to take charge of certain pieces, and he did have interpretative ideas that he was happy to share. “They grow in a lifetime of music,” he said. “The older you get, when you play Beethoven, Brahms and Tchaikovsky all your life, of course, you have certain ideas which you can never really share with the orchestra unless you start conducting.”

Those engagements where he was both soloist and leader led him to conducting — not as just a kind of sideline but as a serious pursuit. “I really wanted to do it properly and to get all the basics,” he said. “It is a completely different profession. Many soloists start conducting without ever actually having learned conducting, because one just simply thinks, ‘Well, I’ve stood on stage all my life, so I know the pieces, I know the scores.’ In my opinion, it’s not enough.”

Rachlin sought advice from famed conductor Mariss Jansons, a family friend whom he describes as something of a second father. “The only person whom I trust is your mother,” Rachlin recalled Jansons telling him. Sophie Rachlin, Julian’s mother, graduated from the St. Petersburg Conservatory in Russia, where she received a diploma in conducting and piano. “My mother graduated in conducting with Jansons, [Valery] Gergiev and [Yuri] Temirkanov at the time,” he said. “She graduated in choir conducting, but still, every one of these great conductors, they all had to do choir conducting as well. And the teachers there were just amazing. It was the golden era.”

Jansons told the violinist to go study with his mother and told Rachlin he didn’t want to hear from him again about conducting for at least five years. “So he was really tough, and I’m so grateful to him for being so hard on me,” he said. Rachlin admits to being reluctant about the idea of working with his mother, but he decided to give it a try in 2005. “So I took one lesson and I was so impressed,” Rachlin said. “Then I went in for a second one, and after five years, we showed a video to Mariss,” he said. The older conductor was impressed with what he saw and told Rachlin to continue with the pursuit. The violinist also received encouragement from other notable conductors such as Lorin Maazel and Daniele Gatti.

“I wanted to know, genuinely, from them if I should continue or if I’m out of my mind and I should not do that,” Rachlin said. “And all of these wonderful musicians, they encouraged me, so that gave me the belief. I never expected it to develop in the direction that it is, but yeah, it’s becoming really serious.”

In his CSO program, Rachlin will serve as soloist and conduct Antonio Vivaldi’s celebrated 1723 set of four violin concertos, The Four Seasons, and Astor Piazzolla’s The Four Seasons of Buenos Aires. The latter consists of four tango compositions that the composer originally considered to be independent works written for his quintet of violin (or viola), piano, electric guitar, double bass and bandoneón. (Also on the lineup will be Mozart’s Divertimento in D Major, K. 136.) About 20 years ago, the Russian composer Leonid Desyatnikov created an arrangement of the four pieces for solo violin and orchestra, structuring them in a way that provides a more direct link to Vivaldi’s precedent-setting creation.

Rachlin performs Piazzolla’s Four Seasons with some regularity. “There are places where I do it a lot and then I let it rest,” he said. “Like with all repertoire, it’s good to have some periods when pieces rest. Only then can they grow. Only then can you have new ideas and fresh ideas. And now it’s a time when I have taken out these so-called Eight Seasons.”

Of his CSO conducting debut, he said, “I’m very, very much looking forward to it. Of course, it’s a great honor. It’s one of the greatest orchestras in the world with such an incredible tradition. The last time [here], I played the Berg Violin Concerto, and I’m so happy to be back with a very popular program.”