A haloalkalitolerant xylanase-producing Bacillus pumilus strain, GESF1 was isolated from an experimental salt farm of CSMCRI. Birch wood xylan and xylose induced maximum xylanase production with considerable activity seen in wheat straw and no activity at all with caboxymethyl cellulose (CMC). A three step purification yielded 21.21-fold purification with a specific activity of 112.42 U/mg protein (unit expressed as ${mu}$mole of xylose released per min). Xylanase produced showed an optimum activity at pH 8.0, with approximately 50 and 30% relative activity at a pH 6.0 and 10.0, respectively. The temperature optimum was $40^{circ}C$ and kinetic properties such as $K_m$ and $V_{max}$ were 5.3 mg/mL and 0.42 ${mu}$mol/min/mL (6593.4 ${mu}$mol/min/mg protein). Xylanase activity (160 ~ 120%) was considerably enhanced in 2.5 to 7.5% NaCl with 87 and 73% retention of activity in 10 and 15% of NaCl. Enzyme activity was enhanced by $Ca^{2+}$, $Mn^{2+}$, $Mg^{2+}$, and $Na^+$ but strongly inhibited by heavy metals such as $Hg^{2+}$, $Fe^{3+}$, $Cu^{2+}$, $Cd^{2+}$, and $Zn^{2+}$. Organic reagents such as ${eta}$-Mercaptoethanol enhanced xylanase activity whereas EDTA strongly inhibited its activity. Xylanase, purified from the Bacillus pumilus strain, GESF1 could have potential biotechnological applications.