Investor qualms about spending and growth drove the stock below $75 per share in extended trading. Najarian believes that the company's success and its spending go hand-in-hand. He pointed to the platform's mobile users, which increased 34 percent year-over-year.
Read MoreFacebook earnings glow on mobile ads, video views
Though the stock has floated nearly 40 percent higher in the last year, it still has room to climb, he said. Najarian added that he bought Facebook options on Wednesday.
Trader Steve Grasso owns Facebook stock already, and the earnings report reinforced his confidence in the stock. Its growth in video makes it more appealing relative to Twitter, which Grasso also owns.
"I'm staying long Facebook," he said.
Read MoreCan mobile help Facebook keep up growth?
While he will watch how Facebook monetizes properties like WhatsApp, trader Tim Seymour also likes Facebook stock at its current level. Trader Karen Finerman expressed less enthusiasm about Facebook as a long play, but said she "wouldn't short it."
Steve Grasso is long AAPL, BA, CLVS, EVGN, FB, GDX, GOOGL, IMMR, KBH, KDUS, MHY, MJNA, NVIV, PFE, POT, SO, T, TMUS, TWTR and YHOO. His firm is long AXP, USO, AMZN, FCX, NE, NEM, OXY, RIG and VALE. His kids are long EFG, EFA, EWJ, IJR and SPY.
Pete Najarian is Long AAPL, BABA, BAC, BHP puts, CSX, DB, EBAY, INTC, JPM, KKR, KO, LLY, LOCO, MRK and ODP. He is long calls AA, AAL, ABX, APD, ARCP, BABA, BIC, BBRY, CY, DAL, DD, DNKN, EBAY, EWG, FB, FCX, GS, GT, HCBK, IAG, ISIL, JPM, MAS, MCD, MS, PEP, POST, RF, SPY, SYY, TWTR, UAL, VGK, WU and XLF. Today, he bought BHP puts and FB calls.
Karen Finerman is long BABA, BAC, C, CVS, FINL, FL, FRO, GOOG, GOOGL, JPM, KORS, M, MTW and NAP. She is short DIA. Her firm is long AAPL, BAC, PLCE, C, CMLS, CVS, DIS, FBT, FINL, FL, GOOG, GOOGL, GPS, IBB, JPM, KORS, M, MTW, NNA, NAP, SUNE and XBI. Her firm is long calls C, JPM spreads, MTW and SUNE. Her firm is short USO, DIA and JPM calls. Karen Finerman is on the board of GrafTech International.
Tim Seymour is long AAPL, BAC, C, DIS, F, GE, GM, GOOGL, INTC, BX, PBR and SUNE. Tim's firm is long BABA, BIDU, CCU, DSKY, KNDI, MCD, NKE, NOK, SINA, SBUX, TSL and VIP.